needed for thread_with_file; also rare but not unheard of to need this
in module code, when blocking on user input.
one workaround used by some code is wait_event_interruptible() - but
that can be buggy if the outer context isn't expecting unwinding.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: fuyuanli <fuyuanli@didiglobal.com>
Current release - regressions:
- af_unix: fix another unix GC hangup
Previous releases - regressions:
- core: fix a possible AF_UNIX deadlock
- bpf: fix NULL pointer dereference in sk_psock_verdict_data_ready()
- netfilter: nft_flow_offload: release dst in case direct xmit path is used
- bridge: switchdev: ensure MDB events are delivered exactly once
- l2tp: pass correct message length to ip6_append_data
- dccp/tcp: unhash sk from ehash for tb2 alloc failure after check_estalblished()
- tls: fixes for record type handling with PEEK
- devlink: fix possible use-after-free and memory leaks in devlink_init()
Previous releases - always broken:
- bpf: fix an oops when attempting to read the vsyscall
page through bpf_probe_read_kernel
- sched: act_mirred: use the backlog for mirred ingress
- netfilter: nft_flow_offload: fix dst refcount underflow
- ipv6: sr: fix possible use-after-free and null-ptr-deref
- mptcp: fix several data races
- phonet: take correct lock to peek at the RX queue
Misc:
- handful of fixes and reliability improvements for selftests
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-6.8.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Including fixes from bpf and netfilter.
Current release - regressions:
- af_unix: fix another unix GC hangup
Previous releases - regressions:
- core: fix a possible AF_UNIX deadlock
- bpf: fix NULL pointer dereference in sk_psock_verdict_data_ready()
- netfilter: nft_flow_offload: release dst in case direct xmit path
is used
- bridge: switchdev: ensure MDB events are delivered exactly once
- l2tp: pass correct message length to ip6_append_data
- dccp/tcp: unhash sk from ehash for tb2 alloc failure after
check_estalblished()
- tls: fixes for record type handling with PEEK
- devlink: fix possible use-after-free and memory leaks in
devlink_init()
Previous releases - always broken:
- bpf: fix an oops when attempting to read the vsyscall page through
bpf_probe_read_kernel
- sched: act_mirred: use the backlog for mirred ingress
- netfilter: nft_flow_offload: fix dst refcount underflow
- ipv6: sr: fix possible use-after-free and null-ptr-deref
- mptcp: fix several data races
- phonet: take correct lock to peek at the RX queue
Misc:
- handful of fixes and reliability improvements for selftests"
* tag 'net-6.8.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (72 commits)
l2tp: pass correct message length to ip6_append_data
net: phy: realtek: Fix rtl8211f_config_init() for RTL8211F(D)(I)-VD-CG PHY
selftests: ioam: refactoring to align with the fix
Fix write to cloned skb in ipv6_hop_ioam()
phonet/pep: fix racy skb_queue_empty() use
phonet: take correct lock to peek at the RX queue
net: sparx5: Add spinlock for frame transmission from CPU
net/sched: flower: Add lock protection when remove filter handle
devlink: fix port dump cmd type
net: stmmac: Fix EST offset for dwmac 5.10
tools: ynl: don't leak mcast_groups on init error
tools: ynl: make sure we always pass yarg to mnl_cb_run
net: mctp: put sock on tag allocation failure
netfilter: nf_tables: use kzalloc for hook allocation
netfilter: nf_tables: register hooks last when adding new chain/flowtable
netfilter: nft_flow_offload: release dst in case direct xmit path is used
netfilter: nft_flow_offload: reset dst in route object after setting up flow
netfilter: nf_tables: set dormant flag on hook register failure
selftests: tls: add test for peeking past a record of a different type
selftests: tls: add test for merging of same-type control messages
...
- While working on the ring buffer I noticed that the counter used
for knowing where the end of the data is on a sub-buffer was not
a full "int" but just 20 bits. It was masked out to 0xfffff.
With the new code that allows the user to change the size of the
sub-buffer, it is theoretically possible to ask for a size
bigger than 2^20. If that happens, unexpected results may
occur as there's no code checking if the counter overflowed the
20 bits of the write mask. There are other checks to make sure
events fit in the sub-buffer, but if the sub-buffer itself is
too big, that is not checked.
Add a check in the resize of the sub-buffer to make sure that it
never goes beyond the size of the counter that holds how much
data is on it.
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Merge tag 'trace-v6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fix from Steven Rostedt:
- While working on the ring buffer I noticed that the counter used for
knowing where the end of the data is on a sub-buffer was not a full
"int" but just 20 bits. It was masked out to 0xfffff.
With the new code that allows the user to change the size of the
sub-buffer, it is theoretically possible to ask for a size bigger
than 2^20. If that happens, unexpected results may occur as there's
no code checking if the counter overflowed the 20 bits of the write
mask. There are other checks to make sure events fit in the
sub-buffer, but if the sub-buffer itself is too big, that is not
checked.
Add a check in the resize of the sub-buffer to make sure that it
never goes beyond the size of the counter that holds how much data is
on it.
* tag 'trace-v6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Do not let subbuf be bigger than write mask
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
pull-request: bpf 2024-02-22
The following pull-request contains BPF updates for your *net* tree.
We've added 11 non-merge commits during the last 24 day(s) which contain
a total of 15 files changed, 217 insertions(+), 17 deletions(-).
The main changes are:
1) Fix a syzkaller-triggered oops when attempting to read the vsyscall
page through bpf_probe_read_kernel and friends, from Hou Tao.
2) Fix a kernel panic due to uninitialized iter position pointer in
bpf_iter_task, from Yafang Shao.
3) Fix a race between bpf_timer_cancel_and_free and bpf_timer_cancel,
from Martin KaFai Lau.
4) Fix a xsk warning in skb_add_rx_frag() (under CONFIG_DEBUG_NET)
due to incorrect truesize accounting, from Sebastian Andrzej Siewior.
5) Fix a NULL pointer dereference in sk_psock_verdict_data_ready,
from Shigeru Yoshida.
6) Fix a resolve_btfids warning when bpf_cpumask symbol cannot be
resolved, from Hari Bathini.
bpf-for-netdev
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf, sockmap: Fix NULL pointer dereference in sk_psock_verdict_data_ready()
selftests/bpf: Add negtive test cases for task iter
bpf: Fix an issue due to uninitialized bpf_iter_task
selftests/bpf: Test racing between bpf_timer_cancel_and_free and bpf_timer_cancel
bpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel
selftest/bpf: Test the read of vsyscall page under x86-64
x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()
x86/mm: Move is_vsyscall_vaddr() into asm/vsyscall.h
bpf, scripts: Correct GPL license name
xsk: Add truesize to skb_add_rx_frag().
bpf: Fix warning for bpf_cpumask in verifier
====================
Link: https://lore.kernel.org/r/20240221231826.1404-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The data on the subbuffer is measured by a write variable that also
contains status flags. The counter is just 20 bits in length. If the
subbuffer is bigger than then counter, it will fail.
Make sure that the subbuffer can not be set to greater than the counter
that keeps track of the data on the subbuffer.
Link: https://lore.kernel.org/linux-trace-kernel/20240220095112.77e9cb81@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 2808e31ec1 ("ring-buffer: Add interface for configuring trace sub buffer size")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
On some systems, sys_membarrier can be very expensive, causing overall
slowdowns for everything. So put a lock on the path in order to
serialize the accesses to prevent the ability for this to be called at
too high of a frequency and saturate the machine.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-and-tested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Fixes: 22e4ebb975 ("membarrier: Provide expedited private command")
Fixes: c5f58bd58f ("membarrier: Provide GLOBAL_EXPEDITED command")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Failure to initialize it->pos, coupled with the presence of an invalid
value in the flags variable, can lead to it->pos referencing an invalid
task, potentially resulting in a kernel panic. To mitigate this risk, it's
crucial to ensure proper initialization of it->pos to NULL.
Fixes: ac8148d957 ("bpf: bpf_iter_task_next: use next_task(kit->task) rather than next_task(kit->pos)")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/bpf/20240217114152.1623-2-laoar.shao@gmail.com
The following race is possible between bpf_timer_cancel_and_free
and bpf_timer_cancel. It will lead a UAF on the timer->timer.
bpf_timer_cancel();
spin_lock();
t = timer->time;
spin_unlock();
bpf_timer_cancel_and_free();
spin_lock();
t = timer->timer;
timer->timer = NULL;
spin_unlock();
hrtimer_cancel(&t->timer);
kfree(t);
/* UAF on t */
hrtimer_cancel(&t->timer);
In bpf_timer_cancel_and_free, this patch frees the timer->timer
after a rcu grace period. This requires a rcu_head addition
to the "struct bpf_hrtimer". Another kfree(t) happens in bpf_timer_init,
this does not need a kfree_rcu because it is still under the
spin_lock and timer->timer has not been visible by others yet.
In bpf_timer_cancel, rcu_read_lock() is added because this helper
can be used in a non rcu critical section context (e.g. from
a sleepable bpf prog). Other timer->timer usages in helpers.c
have been audited, bpf_timer_cancel() is the only place where
timer->timer is used outside of the spin_lock.
Another solution considered is to mark a t->flag in bpf_timer_cancel
and clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free,
it busy waits for the flag to be cleared before kfree(t). This patch
goes with a straight forward solution and frees timer->timer after
a rcu grace period.
Fixes: b00628b1c7 ("bpf: Introduce bpf timers.")
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/bpf/20240215211218.990808-1-martin.lau@linux.dev
- tracing/probes: Fix BTF structure member finder to find the members
which are placed after any anonymous union member correctly.
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Merge tag 'probes-fixes-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes fix from Masami Hiramatsu:
- tracing/probes: Fix BTF structure member finder to find the members
which are placed after any anonymous union member correctly.
* tag 'probes-fixes-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/probes: Fix to search structure fields correctly
Fix to search a field from the structure which has anonymous union
correctly.
Since the reference `type` pointer was updated in the loop, the search
loop suddenly aborted where it hits an anonymous union. Thus it can not
find the field after the anonymous union. This avoids updating the
cursor `type` pointer in the loop.
Link: https://lore.kernel.org/all/170791694361.389532.10047514554799419688.stgit@devnote2/
Fixes: 302db0f5b3 ("tracing/probes: Add a function to search a member of a struct/union")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Just one patch to revert ca10d851b9 ("workqueue: Override implicit ordered
attribute in workqueue_apply_unbound_cpumask()"). This could break ordering
guarantee for ordered workqueues. The problem that the commit tried to
resolve partially - making ordered workqueues follow unbound cpumask - is
fully solved in wq/for-6.9 branch.
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Merge tag 'wq-for-6.8-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
"Just one patch to revert commit ca10d851b9 ("workqueue: Override
implicit ordered attribute in workqueue_apply_unbound_cpumask()").
This commit could break ordering guarantees for ordered workqueues.
The problem that the commit tried to resolve partially - making
ordered workqueues follow unbound cpumask - is fully solved in
wq/for-6.9 branch"
* tag 'wq-for-6.8-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
Revert "workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()"
- Fix the #ifndef that didn't have CONFIG_ on HAVE_DYNAMIC_FTRACE_WITH_REGS
The fix to have dynamic trampolines work with x86 broke arm64 as
the config used in the #ifdef was HAVE_DYNAMIC_FTRACE_WITH_REGS and not
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which removed the fix that the
previous fix was to fix.
- Fix tracing_on state
The code to test if "tracing_on" is set used ring_buffer_record_is_on()
which returns false if the ring buffer isn't able to be written to.
But the ring buffer disable has several bits that disable it.
One is internal disabling which is used for resizing and other
modifications of the ring buffer. But the "tracing_on" user space
visible flag should only report if tracing is actually on and not
internally disabled, as this can cause confusion as writing "1"
when it is disabled will not enable it.
Instead use ring_buffer_record_is_set_on() which shows the user space
visible settings.
- Fix a false positive kmemleak on saved cmdlines
Now that the saved_cmdlines structure is allocated via alloc_page()
and not via kmalloc() it has become invisible to kmemleak.
The allocation done to one of its pointers was flagged as a
dangling allocation leak. Make kmemleak aware of this allocation
and free.
- Fix synthetic event dynamic strings.
A update that cleaned up the synthetic event code removed the
return value of trace_string(), and had it return zero instead
of the length, causing dynamic strings in the synthetic event
to always have zero size.
- Clean up documentation and header files for seq_buf
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Merge tag 'trace-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix the #ifndef that didn't have the 'CONFIG_' prefix on
HAVE_DYNAMIC_FTRACE_WITH_REGS
The fix to have dynamic trampolines work with x86 broke arm64 as the
config used in the #ifdef was HAVE_DYNAMIC_FTRACE_WITH_REGS and not
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which removed the fix that the
previous fix was to fix.
- Fix tracing_on state
The code to test if "tracing_on" is set incorrectly used
ring_buffer_record_is_on() which returns false if the ring buffer
isn't able to be written to.
But the ring buffer disable has several bits that disable it. One is
internal disabling which is used for resizing and other modifications
of the ring buffer. But the "tracing_on" user space visible flag
should only report if tracing is actually on and not internally
disabled, as this can cause confusion as writing "1" when it is
disabled will not enable it.
Instead use ring_buffer_record_is_set_on() which shows the user space
visible settings.
- Fix a false positive kmemleak on saved cmdlines
Now that the saved_cmdlines structure is allocated via alloc_page()
and not via kmalloc() it has become invisible to kmemleak. The
allocation done to one of its pointers was flagged as a dangling
allocation leak. Make kmemleak aware of this allocation and free.
- Fix synthetic event dynamic strings
An update that cleaned up the synthetic event code removed the return
value of trace_string(), and had it return zero instead of the
length, causing dynamic strings in the synthetic event to always have
zero size.
- Clean up documentation and header files for seq_buf
* tag 'trace-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
seq_buf: Fix kernel documentation
seq_buf: Don't use "proxy" headers
tracing/synthetic: Fix trace_string() return value
tracing: Inform kmemleak of saved_cmdlines allocation
tracing: Use ring_buffer_record_is_set_on() in tracer_tracing_is_on()
tracing: Fix HAVE_DYNAMIC_FTRACE_WITH_REGS ifdef
Fix trace_string() by assigning the string length to the return variable
which got lost in commit ddeea494a1 ("tracing/synthetic: Use union
instead of casts") and caused trace_string() to always return 0.
Link: https://lore.kernel.org/linux-trace-kernel/20240214220555.711598-1-thorsten.blum@toblux.com
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: ddeea494a1 ("tracing/synthetic: Use union instead of casts")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Compiling with CONFIG_BPF_SYSCALL & !CONFIG_BPF_JIT throws the below
warning:
"WARN: resolve_btfids: unresolved symbol bpf_cpumask"
Fix it by adding the appropriate #ifdef.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20240208100115.602172-1-hbathini@linux.ibm.com
tracer_tracing_is_on() checks whether record_disabled is not zero. This
checks both the record_disabled counter and the RB_BUFFER_OFF flag.
Reading the source it looks like this function should only check for
the RB_BUFFER_OFF flag. Therefore use ring_buffer_record_is_set_on().
This fixes spurious fails in the 'test for function traceon/off triggers'
test from the ftrace testsuite when the system is under load.
Link: https://lore.kernel.org/linux-trace-kernel/20240205065340.2848065-1-svens@linux.ibm.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Tested-By: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Commit a8b9cf62ad ("ftrace: Fix DIRECT_CALLS to use SAVE_REGS by
default") attempted to fix an issue with direct trampolines on x86, see
its description for details. However, it wrongly referenced the
HAVE_DYNAMIC_FTRACE_WITH_REGS config option and the problem is still
present.
Add the missing "CONFIG_" prefix for the logic to work as intended.
Link: https://lore.kernel.org/linux-trace-kernel/20240213132434.22537-1-petr.pavlu@suse.com
Fixes: a8b9cf62ad ("ftrace: Fix DIRECT_CALLS to use SAVE_REGS by default")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
timers have been migrated on the CPU down path and thus said timer
will get ignored
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Merge tag 'timers_urgent_for_v6.8_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Borislav Petkov:
- Make sure a warning is issued when a hrtimer gets queued after the
timers have been migrated on the CPU down path and thus said timer
will get ignored
* tag 'timers_urgent_for_v6.8_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hrtimer: Report offline hrtimer enqueue
issues or aren't considered to be needed in earlier kernel versions.
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Merge tag 'mm-hotfixes-stable-2024-02-10-11-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"21 hotfixes. 12 are cc:stable and the remainder pertain to post-6.7
issues or aren't considered to be needed in earlier kernel versions"
* tag 'mm-hotfixes-stable-2024-02-10-11-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (21 commits)
nilfs2: fix potential bug in end_buffer_async_write
mm/damon/sysfs-schemes: fix wrong DAMOS tried regions update timeout setup
nilfs2: fix hang in nilfs_lookup_dirty_data_buffers()
MAINTAINERS: Leo Yan has moved
mm/zswap: don't return LRU_SKIP if we have dropped lru lock
fs,hugetlb: fix NULL pointer dereference in hugetlbs_fill_super
mailmap: switch email address for John Moon
mm: zswap: fix objcg use-after-free in entry destruction
mm/madvise: don't forget to leave lazy MMU mode in madvise_cold_or_pageout_pte_range()
arch/arm/mm: fix major fault accounting when retrying under per-VMA lock
selftests: core: include linux/close_range.h for CLOSE_RANGE_* macros
mm/memory-failure: fix crash in split_huge_page_to_list from soft_offline_page
mm: memcg: optimize parent iteration in memcg_rstat_updated()
nilfs2: fix data corruption in dsync block recovery for small block sizes
mm/userfaultfd: UFFDIO_MOVE implementation should use ptep_get()
exit: wait_task_zombie: kill the no longer necessary spin_lock_irq(siglock)
fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats
fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of lock_task_sighand()
getrusage: use sig->stats_lock rather than lock_task_sighand()
getrusage: move thread_group_cputime_adjusted() outside of lock_task_sighand()
...
- Fix broken direct trampolines being called when another callback is
attached the same function. ARM 64 does not support FTRACE_WITH_REGS, and
when it added direct trampoline calls from ftrace, it removed the
"WITH_REGS" flag from the ftrace_ops for direct trampolines. This broke
x86 as x86 requires direct trampolines to have WITH_REGS. This wasn't
noticed because direct trampolines work as long as the function it is
attached to is not shared with other callbacks (like the function tracer).
When there's other callbacks, a helper trampoline is called, to call all
the non direct callbacks and when it returns, the direct trampoline is
called. For x86, the direct trampoline sets a flag in the regs field to
tell the x86 specific code to call the direct trampoline. But this only
works if the ftrace_ops had WITH_REGS set. ARM does things differently
that does not require this. For now, set WITH_REGS if the arch supports
WITH_REGS (which ARM does not), and this makes it work for both ARM64 and
x86.
- Fix wasted memory in the saved_cmdlines logic.
The saved_cmdlines is a cache that maps PIDs to COMMs that tracing can
use. Most trace events only save the PID in the event. The saved_cmdlines
file lists PIDs to COMMs so that the tracing tools can show an actual name
and not just a PID for each event. There's an array of PIDs that map to a
small set of saved COMM strings. The array is set to PID_MAX_DEFAULT which
is usually set to 32768. When a PID comes in, it will add itself to this
array along with the index into the COMM array (note if the system allows
more than PID_MAX_DEFAULT, this cache is similar to cache lines as an
update of a PID that has the same PID_MAX_DEFAULT bits set will flush out
another task with the same matching bits set).
A while ago, the size of this cache was changed to be dynamic and the
array was moved into a structure and created with kmalloc(). But this
new structure had the size of 131104 bytes, or 0x20020 in hex. As kmalloc
allocates in powers of two, it was actually allocating 0x40000 bytes
(262144) leaving 131040 bytes of wasted memory. The last element of this
structure was a pointer to the COMM string array which defaulted to just
saving 128 COMMs.
By changing the last field of this structure to a variable length string,
and just having it round up to fill the allocated memory, the default
size of the saved COMM cache is now 8190. This not only uses the wasted
space, but actually saves space by removing the extra allocation for the
COMM names.
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Merge tag 'trace-v6.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix broken direct trampolines being called when another callback is
attached the same function.
ARM 64 does not support FTRACE_WITH_REGS, and when it added direct
trampoline calls from ftrace, it removed the "WITH_REGS" flag from
the ftrace_ops for direct trampolines. This broke x86 as x86 requires
direct trampolines to have WITH_REGS.
This wasn't noticed because direct trampolines work as long as the
function it is attached to is not shared with other callbacks (like
the function tracer). When there are other callbacks, a helper
trampoline is called, to call all the non direct callbacks and when
it returns, the direct trampoline is called.
For x86, the direct trampoline sets a flag in the regs field to tell
the x86 specific code to call the direct trampoline. But this only
works if the ftrace_ops had WITH_REGS set. ARM does things
differently that does not require this. For now, set WITH_REGS if the
arch supports WITH_REGS (which ARM does not), and this makes it work
for both ARM64 and x86.
- Fix wasted memory in the saved_cmdlines logic.
The saved_cmdlines is a cache that maps PIDs to COMMs that tracing
can use. Most trace events only save the PID in the event. The
saved_cmdlines file lists PIDs to COMMs so that the tracing tools can
show an actual name and not just a PID for each event. There's an
array of PIDs that map to a small set of saved COMM strings. The
array is set to PID_MAX_DEFAULT which is usually set to 32768. When a
PID comes in, it will add itself to this array along with the index
into the COMM array (note if the system allows more than
PID_MAX_DEFAULT, this cache is similar to cache lines as an update of
a PID that has the same PID_MAX_DEFAULT bits set will flush out
another task with the same matching bits set).
A while ago, the size of this cache was changed to be dynamic and the
array was moved into a structure and created with kmalloc(). But this
new structure had the size of 131104 bytes, or 0x20020 in hex. As
kmalloc allocates in powers of two, it was actually allocating
0x40000 bytes (262144) leaving 131040 bytes of wasted memory. The
last element of this structure was a pointer to the COMM string array
which defaulted to just saving 128 COMMs.
By changing the last field of this structure to a variable length
string, and just having it round up to fill the allocated memory, the
default size of the saved COMM cache is now 8190. This not only uses
the wasted space, but actually saves space by removing the extra
allocation for the COMM names.
* tag 'trace-v6.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix wasted memory in saved_cmdlines logic
ftrace: Fix DIRECT_CALLS to use SAVE_REGS by default
While looking at improving the saved_cmdlines cache I found a huge amount
of wasted memory that should be used for the cmdlines.
The tracing data saves pids during the trace. At sched switch, if a trace
occurred, it will save the comm of the task that did the trace. This is
saved in a "cache" that maps pids to comms and exposed to user space via
the /sys/kernel/tracing/saved_cmdlines file. Currently it only caches by
default 128 comms.
The structure that uses this creates an array to store the pids using
PID_MAX_DEFAULT (which is usually set to 32768). This causes the structure
to be of the size of 131104 bytes on 64 bit machines.
In hex: 131104 = 0x20020, and since the kernel allocates generic memory in
powers of two, the kernel would allocate 0x40000 or 262144 bytes to store
this structure. That leaves 131040 bytes of wasted space.
Worse, the structure points to an allocated array to store the comm names,
which is 16 bytes times the amount of names to save (currently 128), which
is 2048 bytes. Instead of allocating a separate array, make the structure
end with a variable length string and use the extra space for that.
This is similar to a recommendation that Linus had made about eventfs_inode names:
https://lore.kernel.org/all/20240130190355.11486-5-torvalds@linux-foundation.org/
Instead of allocating a separate string array to hold the saved comms,
have the structure end with: char saved_cmdlines[]; and round up to the
next power of two over sizeof(struct saved_cmdline_buffers) + num_cmdlines * TASK_COMM_LEN
It will use this extra space for the saved_cmdline portion.
Now, instead of saving only 128 comms by default, by using this wasted
space at the end of the structure it can save over 8000 comms and even
saves space by removing the need for allocating the other array.
Link: https://lore.kernel.org/linux-trace-kernel/20240209063622.1f7b6d5f@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Mete Durlu <meted@linux.ibm.com>
Fixes: 939c7a4f04 ("tracing: Introduce saved_cmdlines_size file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The commit 60c8971899 ("ftrace: Make DIRECT_CALLS work WITH_ARGS
and !WITH_REGS") changed DIRECT_CALLS to use SAVE_ARGS when there
are multiple ftrace_ops at the same function, but since the x86 only
support to jump to direct_call from ftrace_regs_caller, when we set
the function tracer on the same target function on x86, ftrace-direct
does not work as below (this actually works on arm64.)
At first, insmod ftrace-direct.ko to put a direct_call on
'wake_up_process()'.
# insmod kernel/samples/ftrace/ftrace-direct.ko
# less trace
...
<idle>-0 [006] ..s1. 564.686958: my_direct_func: waking up rcu_preempt-17
<idle>-0 [007] ..s1. 564.687836: my_direct_func: waking up kcompactd0-63
<idle>-0 [006] ..s1. 564.690926: my_direct_func: waking up rcu_preempt-17
<idle>-0 [006] ..s1. 564.696872: my_direct_func: waking up rcu_preempt-17
<idle>-0 [007] ..s1. 565.191982: my_direct_func: waking up kcompactd0-63
Setup a function filter to the 'wake_up_process' too, and enable it.
# cd /sys/kernel/tracing/
# echo wake_up_process > set_ftrace_filter
# echo function > current_tracer
# less trace
...
<idle>-0 [006] ..s3. 686.180972: wake_up_process <-call_timer_fn
<idle>-0 [006] ..s3. 686.186919: wake_up_process <-call_timer_fn
<idle>-0 [002] ..s3. 686.264049: wake_up_process <-call_timer_fn
<idle>-0 [002] d.h6. 686.515216: wake_up_process <-kick_pool
<idle>-0 [002] d.h6. 686.691386: wake_up_process <-kick_pool
Then, only function tracer is shown on x86.
But if you enable 'kprobe on ftrace' event (which uses SAVE_REGS flag)
on the same function, it is shown again.
# echo 'p wake_up_process' >> dynamic_events
# echo 1 > events/kprobes/p_wake_up_process_0/enable
# echo > trace
# less trace
...
<idle>-0 [006] ..s2. 2710.345919: p_wake_up_process_0: (wake_up_process+0x4/0x20)
<idle>-0 [006] ..s3. 2710.345923: wake_up_process <-call_timer_fn
<idle>-0 [006] ..s1. 2710.345928: my_direct_func: waking up rcu_preempt-17
<idle>-0 [006] ..s2. 2710.349931: p_wake_up_process_0: (wake_up_process+0x4/0x20)
<idle>-0 [006] ..s3. 2710.349934: wake_up_process <-call_timer_fn
<idle>-0 [006] ..s1. 2710.349937: my_direct_func: waking up rcu_preempt-17
To fix this issue, use SAVE_REGS flag for multiple ftrace_ops flag of
direct_call by default.
Link: https://lore.kernel.org/linux-trace-kernel/170484558617.178953.1590516949390270842.stgit@devnote2
Fixes: 60c8971899 ("ftrace: Make DIRECT_CALLS work WITH_ARGS and !WITH_REGS")
Cc: stable@vger.kernel.org
Cc: Florent Revest <revest@chromium.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
ri and sym is assigned first, so it does not need to initialize the
assignment.
Link: https://lore.kernel.org/all/20230919012823.7815-1-zeming@nfschina.com/
Signed-off-by: Li zeming <zeming@nfschina.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fix to show a parse error for bad type (non-string) for $comm/$COMM and
immediate-string. With this fix, error_log file shows appropriate error
message as below.
/sys/kernel/tracing # echo 'p vfs_read $comm:u32' >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/tracing # echo 'p vfs_read \"hoge":u32' >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/tracing # cat error_log
[ 30.144183] trace_kprobe: error: $comm and immediate-string only accepts string type
Command: p vfs_read $comm:u32
^
[ 62.618500] trace_kprobe: error: $comm and immediate-string only accepts string type
Command: p vfs_read \"hoge":u32
^
Link: https://lore.kernel.org/all/170602215411.215583.2238016352271091852.stgit@devnote2/
Fixes: 3dd1f7f24f ("tracing: probeevent: Fix to make the type of $comm string")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
After the recent changes nobody use siglock to read the values protected
by stats_lock, we can kill spin_lock_irq(¤t->sighand->siglock) and
update the comment.
With this patch only __exit_signal() and thread_group_start_cputime() take
stats_lock under siglock.
Link: https://lkml.kernel.org/r/20240123153359.GA21866@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Dylan Hatch <dylanbhatch@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
lock_task_sighand() can trigger a hard lockup. If NR_CPUS threads call
getrusage() at the same time and the process has NR_THREADS, spin_lock_irq
will spin with irqs disabled O(NR_CPUS * NR_THREADS) time.
Change getrusage() to use sig->stats_lock, it was specifically designed
for this type of use. This way it runs lockless in the likely case.
TODO:
- Change do_task_stat() to use sig->stats_lock too, then we can
remove spin_lock_irq(siglock) in wait_task_zombie().
- Turn sig->stats_lock into seqcount_rwlock_t, this way the
readers in the slow mode won't exclude each other. See
https://lore.kernel.org/all/20230913154907.GA26210@redhat.com/
- stats_lock has to disable irqs because ->siglock can be taken
in irq context, it would be very nice to change __exit_signal()
to avoid the siglock->stats_lock dependency.
Link: https://lkml.kernel.org/r/20240122155053.GA26214@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Dylan Hatch <dylanbhatch@google.com>
Tested-by: Dylan Hatch <dylanbhatch@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "getrusage: use sig->stats_lock", v2.
This patch (of 2):
thread_group_cputime() does its own locking, we can safely shift
thread_group_cputime_adjusted() which does another for_each_thread loop
outside of ->siglock protected section.
This is also preparation for the next patch which changes getrusage() to
use stats_lock instead of siglock, thread_group_cputime() takes the same
lock. With the current implementation recursive read_seqbegin_or_lock()
is fine, thread_group_cputime() can't enter the slow mode if the caller
holds stats_lock, yet this looks more safe and better performance-wise.
Link: https://lkml.kernel.org/r/20240122155023.GA26169@redhat.com
Link: https://lkml.kernel.org/r/20240122155050.GA26205@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Dylan Hatch <dylanbhatch@google.com>
Tested-by: Dylan Hatch <dylanbhatch@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The hrtimers migration on CPU-down hotplug process has been moved
earlier, before the CPU actually goes to die. This leaves a small window
of opportunity to queue an hrtimer in a blind spot, leaving it ignored.
For example a practical case has been reported with RCU waking up a
SCHED_FIFO task right before the CPUHP_AP_IDLE_DEAD stage, queuing that
way a sched/rt timer to the local offline CPU.
Make sure such situations never go unnoticed and warn when that happens.
Fixes: 5c0930ccaa ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240129235646.3171983-4-boqun.feng@gmail.com
This reverts commit ca10d851b9.
The commit allowed workqueue_apply_unbound_cpumask() to clear __WQ_ORDERED
on now removed implicitly ordered workqueues. This was incorrect in that
system-wide config change shouldn't break ordering properties of all
workqueues. The reason why apply_workqueue_attrs() path was allowed to do so
was because it was targeting the specific workqueue - either the workqueue
had WQ_SYSFS set or the workqueue user specifically tried to change
max_active, both of which indicate that the workqueue doesn't need to be
ordered.
The implicitly ordered workqueue promotion was removed by the previous
commit 3bc1e711c2 ("workqueue: Don't implicitly make UNBOUND workqueues w/
@max_active==1 ordered"). However, it didn't update this path and broke
build. Let's revert the commit which was incorrect in the first place which
also fixes build.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 3bc1e711c2 ("workqueue: Don't implicitly make UNBOUND workqueues w/ @max_active==1 ordered")
Fixes: ca10d851b9 ("workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()")
Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Tejun Heo <tj@kernel.org>
- Fix the return code for ring_buffer_poll_wait()
It was returing a -EINVAL instead of EPOLLERR.
- Zero out the tracefs_inode so that all fields are initialized.
The ti->private could have had stale data, but instead of
just initializing it to NULL, clear out the entire structure
when it is allocated.
- Fix a crash in timerlat
The hrtimer was initialized at read and not open, but is
canceled at close. If the file was opened and never read
the close will pass a NULL pointer to hrtime_cancel().
- Rewrite of eventfs.
Linus wrote a patch series to remove the dentry references in the
eventfs_inode and to use ref counting and more of proper VFS
interfaces to make it work.
- Add warning to put_ei() if ei is not set to free. That means
something is about to free it when it shouldn't.
- Restructure the eventfs_inode to make it more compact, and remove
the unused llist field.
- Remove the fsnotify*() funtions for when the inodes were being created
in the lookup code. It doesn't make sense to notify about creation
just because something is being looked up.
- The inode hard link count was not accurate. It was being updated
when a file was looked up. The inodes of directories were updating
their parent inode hard link count every time the inode was created.
That means if memory reclaim cleaned a stale directory inode and
the inode was lookup up again, it would increment the parent inode
again as well. Al Viro said to just have all eventfs directories
have a hard link count of 1. That tells user space not to trust it.
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Merge tag 'trace-v6.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing and eventfs fixes from Steven Rostedt:
- Fix the return code for ring_buffer_poll_wait()
It was returing a -EINVAL instead of EPOLLERR.
- Zero out the tracefs_inode so that all fields are initialized.
The ti->private could have had stale data, but instead of just
initializing it to NULL, clear out the entire structure when it is
allocated.
- Fix a crash in timerlat
The hrtimer was initialized at read and not open, but is canceled at
close. If the file was opened and never read the close will pass a
NULL pointer to hrtime_cancel().
- Rewrite of eventfs.
Linus wrote a patch series to remove the dentry references in the
eventfs_inode and to use ref counting and more of proper VFS
interfaces to make it work.
- Add warning to put_ei() if ei is not set to free. That means
something is about to free it when it shouldn't.
- Restructure the eventfs_inode to make it more compact, and remove the
unused llist field.
- Remove the fsnotify*() funtions for when the inodes were being
created in the lookup code. It doesn't make sense to notify about
creation just because something is being looked up.
- The inode hard link count was not accurate.
It was being updated when a file was looked up. The inodes of
directories were updating their parent inode hard link count every
time the inode was created. That means if memory reclaim cleaned a
stale directory inode and the inode was lookup up again, it would
increment the parent inode again as well. Al Viro said to just have
all eventfs directories have a hard link count of 1. That tells user
space not to trust it.
* tag 'trace-v6.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
eventfs: Keep all directory links at 1
eventfs: Remove fsnotify*() functions from lookup()
eventfs: Restructure eventfs_inode structure to be more condensed
eventfs: Warn if an eventfs_inode is freed without is_freed being set
tracing/timerlat: Move hrtimer_init to timerlat_fd open()
eventfs: Get rid of dentry pointers without refcounts
eventfs: Clean up dentry ops and add revalidate function
eventfs: Remove unused d_parent pointer field
tracefs: dentry lookup crapectomy
tracefs: Avoid using the ei->dentry pointer unnecessarily
eventfs: Initialize the tracefs inode properly
tracefs: Zero out the tracefs_inode when allocating it
ring-buffer: Clean ring_buffer_poll_wait() error return
The return type for ring_buffer_poll_wait() is __poll_t. This is behind
the scenes an unsigned where we can set event bits. In case of a
non-allocated CPU, we do return instead -EINVAL (0xffffffea). Lucky us,
this ends up setting few error bits (EPOLLERR | EPOLLHUP | EPOLLNVAL), so
user-space at least is aware something went wrong.
Nonetheless, this is an incorrect code. Replace that -EINVAL with a
proper EPOLLERR to clean that output. As this doesn't change the
behaviour, there's no need to treat this change as a bug fix.
Link: https://lore.kernel.org/linux-trace-kernel/20240131140955.3322792-1-vdonnefort@google.com
Cc: stable@vger.kernel.org
Fixes: 6721cb6002 ("ring-buffer: Do not poll non allocated cpu buffers")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- Fix register_snapshot_trigger() on allocation error
If the snapshot fails to allocate, the register_snapshot_trigger() can
still return success. If the call to tracing_alloc_snapshot_instance()
returned anything but 0, it returned 0, but it should have been returning
the error code from that allocation function.
- Remove leftover code from tracefs doing a dentry walk on remount.
The update_gid() function was called by the tracefs code on remount
to update the gid of eventfs, but that is no longer the case, but that
code wasn't deleted. Nothing calls it. Remove it.
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Merge tag 'trace-v6.8-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
"Two small fixes for tracefs and eventfs:
- Fix register_snapshot_trigger() on allocation error
If the snapshot fails to allocate, the register_snapshot_trigger()
can still return success. If the call to
tracing_alloc_snapshot_instance() returned anything but 0, it
returned 0, but it should have been returning the error code from
that allocation function.
- Remove leftover code from tracefs doing a dentry walk on remount.
The update_gid() function was called by the tracefs code on remount
to update the gid of eventfs, but that is no longer the case, but
that code wasn't deleted. Nothing calls it. Remove it"
* tag 'trace-v6.8-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracefs: remove stale 'update_gid' code
tracing/trigger: Fix to return error if failed to alloc snapshot
or aren't considered appropriate for backporting.
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Merge tag 'mm-hotfixes-stable-2024-01-28-23-21' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"22 hotfixes. 11 are cc:stable and the remainder address post-6.7
issues or aren't considered appropriate for backporting"
* tag 'mm-hotfixes-stable-2024-01-28-23-21' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
mm: thp_get_unmapped_area must honour topdown preference
mm: huge_memory: don't force huge page alignment on 32 bit
userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb
selftests/mm: ksm_tests should only MADV_HUGEPAGE valid memory
scs: add CONFIG_MMU dependency for vfree_atomic()
mm/memory: fix folio_set_dirty() vs. folio_mark_dirty() in zap_pte_range()
mm/huge_memory: fix folio_set_dirty() vs. folio_mark_dirty()
selftests/mm: Update va_high_addr_switch.sh to check CPU for la57 flag
selftests: mm: fix map_hugetlb failure on 64K page size systems
MAINTAINERS: supplement of zswap maintainers update
stackdepot: make fast paths lock-less again
stackdepot: add stats counters exported via debugfs
mm, kmsan: fix infinite recursion due to RCU critical section
mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again
selftests/mm: switch to bash from sh
MAINTAINERS: add man-pages git trees
mm: memcontrol: don't throttle dying tasks on memory.high
mm: mmap: map MAP_STACK to VM_NOHUGEPAGE
uprobes: use pagesize-aligned virtual address when replacing pages
selftests/mm: mremap_test: fix build warning
...
exposure
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Merge tag 'locking_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Borislav Petkov:
- Prevent an inconsistent futex operation leading to stale state
exposure
* tag 'locking_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Prevent the reuse of stale pi_state
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Merge tag 'irq_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fix from Borislav Petkov:
- Initialize the resend node of each IRQ descriptor, not only the first
one
* tag 'irq_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Initialize resend_node hlist for all interrupt descriptors
events in order to be able to compute correct averages
- Limit the duration of the clocksource watchdog checking interval as
too long intervals lead to wrongly marking the TSC as unstable
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Merge tag 'timers_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Borislav Petkov:
- Preserve the number of idle calls and sleep entries across CPU
hotplug events in order to be able to compute correct averages
- Limit the duration of the clocksource watchdog checking interval as
too long intervals lead to wrongly marking the TSC as unstable
* tag 'timers_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick/sched: Preserve number of idle sleeps across CPU hotplug events
clocksource: Skip watchdog check for large watchdog intervals
Fix register_snapshot_trigger() to return error code if it failed to
allocate a snapshot instead of 0 (success). Unless that, it will register
snapshot trigger without an error.
Link: https://lore.kernel.org/linux-trace-kernel/170622977792.270660.2789298642759362200.stgit@devnote2
Fixes: 0bbe7f7199 ("tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation")
Cc: stable@vger.kernel.org
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
uprobes passes an unaligned page mapping address to
folio_add_new_anon_rmap(), which ends up triggering a VM_BUG_ON() we
recently extended in commit 372cbd4d5a ("mm: non-pmd-mappable, large
folios for folio_add_new_anon_rmap()").
Arguably, this is uprobes code doing something wrong; however, for the
time being it would have likely worked in rmap code because
__folio_set_anon() would set folio->index to the same value.
Looking at __replace_page(), we'd also pass slightly wrong values to
mmu_notifier_range_init(), page_vma_mapped_walk(), flush_cache_page(),
ptep_clear_flush() and set_pte_at_notify(). I suspect most of them are
fine, but let's just mark the introducing commit as the one needed fixing.
I don't think CC stable is warranted.
We'll add more sanity checks in rmap code separately, to make sure that we
always get properly aligned addresses.
Link: https://lkml.kernel.org/r/20240115100731.91007-1-david@redhat.com
Fixes: c517ee744b ("uprobes: __replace_page() should not use page_address_in_vma()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Jiri Olsa <jolsa@kernel.org>
Closes: https://lkml.kernel.org/r/ZaMR2EWN-HvlCfUl@krava
Tested-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit fixes RCU grace period stalls, which are observed when
an outgoing CPU's quiescent state reporting results in wakeup of
one of the grace period kthreads, to complete the grace period. If
those kthreads have SCHED_FIFO policy, the wake up can indirectly
arm the RT bandwith timer to the local offline CPU. Earlier migration
of the hrtimers from the CPU introduced in commit 5c0930ccaa
("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
results in this timer getting ignored. If the RCU grace period
kthreads are waiting for RT bandwidth to be available, they may
never be actually scheduled, resulting in RCU stall warnings.
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Merge tag 'urgent-rcu.2024.01.24a' of https://github.com/neeraju/linux
Pull RCU fix from Neeraj Upadhyay:
"This fixes RCU grace period stalls, which are observed when an
outgoing CPU's quiescent state reporting results in wakeup of one of
the grace period kthreads, to complete the grace period.
If those kthreads have SCHED_FIFO policy, the wake up can indirectly
arm the RT bandwith timer to the local offline CPU.
Earlier migration of the hrtimers from the CPU introduced in commit
5c0930ccaa ("hrtimers: Push pending hrtimers away from outgoing CPU
earlier") results in this timer getting ignored.
If the RCU grace period kthreads are waiting for RT bandwidth to be
available, they may never be actually scheduled, resulting in RCU
stall warnings"
* tag 'urgent-rcu.2024.01.24a' of https://github.com/neeraju/linux:
rcu: Defer RCU kthreads wakeup when CPU is dying
Commit 71fee48f ("tick-sched: Fix idle and iowait sleeptime accounting vs
CPU hotplug") preserved total idle sleep time and iowait sleeptime across
CPU hotplug events.
Similar reasoning applies to the number of idle calls and idle sleeps to
get the proper average of sleep time per idle invocation.
Preserve those fields too.
Fixes: 71fee48f ("tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug")
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240122233534.3094238-1-tim.c.chen@linux.intel.com
There have been reports of the watchdog marking clocksources unstable on
machines with 8 NUMA nodes:
clocksource: timekeeping watchdog on CPU373:
Marking clocksource 'tsc' as unstable because the skew is too large:
clocksource: 'hpet' wd_nsec: 14523447520
clocksource: 'tsc' cs_nsec: 14524115132
The measured clocksource skew - the absolute difference between cs_nsec
and wd_nsec - was 668 microseconds:
cs_nsec - wd_nsec = 14524115132 - 14523447520 = 667612
The kernel used 200 microseconds for the uncertainty_margin of both the
clocksource and watchdog, resulting in a threshold of 400 microseconds (the
md variable). Both the cs_nsec and the wd_nsec value indicate that the
readout interval was circa 14.5 seconds. The observed behaviour is that
watchdog checks failed for large readout intervals on 8 NUMA node
machines. This indicates that the size of the skew was directly proportinal
to the length of the readout interval on those machines. The measured
clocksource skew, 668 microseconds, was evaluated against a threshold (the
md variable) that is suited for readout intervals of roughly
WATCHDOG_INTERVAL, i.e. HZ >> 1, which is 0.5 second.
The intention of 2e27e793e2 ("clocksource: Reduce clocksource-skew
threshold") was to tighten the threshold for evaluating skew and set the
lower bound for the uncertainty_margin of clocksources to twice
WATCHDOG_MAX_SKEW. Later in c37e85c135 ("clocksource: Loosen clocksource
watchdog constraints"), the WATCHDOG_MAX_SKEW constant was increased to
125 microseconds to fit the limit of NTP, which is able to use a
clocksource that suffers from up to 500 microseconds of skew per second.
Both the TSC and the HPET use default uncertainty_margin. When the
readout interval gets stretched the default uncertainty_margin is no
longer a suitable lower bound for evaluating skew - it imposes a limit
that is far stricter than the skew with which NTP can deal.
The root causes of the skew being directly proportinal to the length of
the readout interval are:
* the inaccuracy of the shift/mult pairs of clocksources and the watchdog
* the conversion to nanoseconds is imprecise for large readout intervals
Prevent this by skipping the current watchdog check if the readout
interval exceeds 2 * WATCHDOG_INTERVAL. Considering the maximum readout
interval of 2 * WATCHDOG_INTERVAL, the current default uncertainty margin
(of the TSC and HPET) corresponds to a limit on clocksource skew of 250
ppm (microseconds of skew per second). To keep the limit imposed by NTP
(500 microseconds of skew per second) for all possible readout intervals,
the margins would have to be scaled so that the threshold value is
proportional to the length of the actual readout interval.
As for why the readout interval may get stretched: Since the watchdog is
executed in softirq context the expiration of the watchdog timer can get
severely delayed on account of a ksoftirqd thread not getting to run in a
timely manner. Surely, a system with such belated softirq execution is not
working well and the scheduling issue should be looked into but the
clocksource watchdog should be able to deal with it accordingly.
Fixes: 2e27e793e2 ("clocksource: Reduce clocksource-skew threshold")
Suggested-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Jiri Wiesner <jwiesner@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240122172350.GA740@incl
Just to help distinguish the fs->in_exec flag from the current->in_execve
flag, add comments in check_unsafe_exec() and copy_fs() for more
context. Also note that in_execve is only used by TOMOYO now.
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
When the CPU goes idle for the last time during the CPU down hotplug
process, RCU reports a final quiescent state for the current CPU. If
this quiescent state propagates up to the top, some tasks may then be
woken up to complete the grace period: the main grace period kthread
and/or the expedited main workqueue (or kworker).
If those kthreads have a SCHED_FIFO policy, the wake up can indirectly
arm the RT bandwith timer to the local offline CPU. Since this happens
after hrtimers have been migrated at CPUHP_AP_HRTIMERS_DYING stage, the
timer gets ignored. Therefore if the RCU kthreads are waiting for RT
bandwidth to be available, they may never be actually scheduled.
This triggers TREE03 rcutorture hangs:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 4-...!: (1 GPs behind) idle=9874/1/0x4000000000000000 softirq=0/0 fqs=20 rcuc=21071 jiffies(starved)
rcu: (t=21035 jiffies g=938281 q=40787 ncpus=6)
rcu: rcu_preempt kthread starved for 20964 jiffies! g938281 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:14896 pid:14 tgid:14 ppid:2 flags:0x00004000
Call Trace:
<TASK>
__schedule+0x2eb/0xa80
schedule+0x1f/0x90
schedule_timeout+0x163/0x270
? __pfx_process_timeout+0x10/0x10
rcu_gp_fqs_loop+0x37c/0x5b0
? __pfx_rcu_gp_kthread+0x10/0x10
rcu_gp_kthread+0x17c/0x200
kthread+0xde/0x110
? __pfx_kthread+0x10/0x10
ret_from_fork+0x2b/0x40
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>
The situation can't be solved with just unpinning the timer. The hrtimer
infrastructure and the nohz heuristics involved in finding the best
remote target for an unpinned timer would then also need to handle
enqueues from an offline CPU in the most horrendous way.
So fix this on the RCU side instead and defer the wake up to an online
CPU if it's too late for the local one.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Fixes: 5c0930ccaa ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
For a CONFIG_SPARSE_IRQ=n kernel, early_irq_init() is supposed to
initialize all interrupt descriptors.
It does except for irq_desc::resend_node, which ia only initialized for the
first descriptor.
Use the indexed decriptor and not the base pointer to address that.
Fixes: bc06a9e087 ("genirq: Use hlist for managing resend handlers")
Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240122085716.2999875-5-dawei.li@shingroup.cn
Running the following two commands in parallel on a multi-processor
AArch64 machine can sporadically produce an unexpected warning about
duplicate histogram entries:
$ while true; do
echo hist:key=id.syscall:val=hitcount > \
/sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
sleep 0.001
done
$ stress-ng --sysbadaddr $(nproc)
The warning looks as follows:
[ 2911.172474] ------------[ cut here ]------------
[ 2911.173111] Duplicates detected: 1
[ 2911.173574] WARNING: CPU: 2 PID: 12247 at kernel/trace/tracing_map.c:983 tracing_map_sort_entries+0x3e0/0x408
[ 2911.174702] Modules linked in: iscsi_ibft(E) iscsi_boot_sysfs(E) rfkill(E) af_packet(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) ena(E) tiny_power_button(E) qemu_fw_cfg(E) button(E) fuse(E) efi_pstore(E) ip_tables(E) x_tables(E) xfs(E) libcrc32c(E) aes_ce_blk(E) aes_ce_cipher(E) crct10dif_ce(E) polyval_ce(E) polyval_generic(E) ghash_ce(E) gf128mul(E) sm4_ce_gcm(E) sm4_ce_ccm(E) sm4_ce(E) sm4_ce_cipher(E) sm4(E) sm3_ce(E) sm3(E) sha3_ce(E) sha512_ce(E) sha512_arm64(E) sha2_ce(E) sha256_arm64(E) nvme(E) sha1_ce(E) nvme_core(E) nvme_auth(E) t10_pi(E) sg(E) scsi_mod(E) scsi_common(E) efivarfs(E)
[ 2911.174738] Unloaded tainted modules: cppc_cpufreq(E):1
[ 2911.180985] CPU: 2 PID: 12247 Comm: cat Kdump: loaded Tainted: G E 6.7.0-default #2 1b58bbb22c97e4399dc09f92d309344f69c44a01
[ 2911.182398] Hardware name: Amazon EC2 c7g.8xlarge/, BIOS 1.0 11/1/2018
[ 2911.183208] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 2911.184038] pc : tracing_map_sort_entries+0x3e0/0x408
[ 2911.184667] lr : tracing_map_sort_entries+0x3e0/0x408
[ 2911.185310] sp : ffff8000a1513900
[ 2911.185750] x29: ffff8000a1513900 x28: ffff0003f272fe80 x27: 0000000000000001
[ 2911.186600] x26: ffff0003f272fe80 x25: 0000000000000030 x24: 0000000000000008
[ 2911.187458] x23: ffff0003c5788000 x22: ffff0003c16710c8 x21: ffff80008017f180
[ 2911.188310] x20: ffff80008017f000 x19: ffff80008017f180 x18: ffffffffffffffff
[ 2911.189160] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000a15134b8
[ 2911.190015] x14: 0000000000000000 x13: 205d373432323154 x12: 5b5d313131333731
[ 2911.190844] x11: 00000000fffeffff x10: 00000000fffeffff x9 : ffffd1b78274a13c
[ 2911.191716] x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 000000000057ffa8
[ 2911.192554] x5 : ffff0012f6c24ec0 x4 : 0000000000000000 x3 : ffff2e5b72b5d000
[ 2911.193404] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0003ff254480
[ 2911.194259] Call trace:
[ 2911.194626] tracing_map_sort_entries+0x3e0/0x408
[ 2911.195220] hist_show+0x124/0x800
[ 2911.195692] seq_read_iter+0x1d4/0x4e8
[ 2911.196193] seq_read+0xe8/0x138
[ 2911.196638] vfs_read+0xc8/0x300
[ 2911.197078] ksys_read+0x70/0x108
[ 2911.197534] __arm64_sys_read+0x24/0x38
[ 2911.198046] invoke_syscall+0x78/0x108
[ 2911.198553] el0_svc_common.constprop.0+0xd0/0xf8
[ 2911.199157] do_el0_svc+0x28/0x40
[ 2911.199613] el0_svc+0x40/0x178
[ 2911.200048] el0t_64_sync_handler+0x13c/0x158
[ 2911.200621] el0t_64_sync+0x1a8/0x1b0
[ 2911.201115] ---[ end trace 0000000000000000 ]---
The problem appears to be caused by CPU reordering of writes issued from
__tracing_map_insert().
The check for the presence of an element with a given key in this
function is:
val = READ_ONCE(entry->val);
if (val && keys_match(key, val->key, map->key_size)) ...
The write of a new entry is:
elt = get_free_elt(map);
memcpy(elt->key, key, map->key_size);
entry->val = elt;
The "memcpy(elt->key, key, map->key_size);" and "entry->val = elt;"
stores may become visible in the reversed order on another CPU. This
second CPU might then incorrectly determine that a new key doesn't match
an already present val->key and subsequently insert a new element,
resulting in a duplicate.
Fix the problem by adding a write barrier between
"memcpy(elt->key, key, map->key_size);" and "entry->val = elt;", and for
good measure, also use WRITE_ONCE(entry->val, elt) for publishing the
element. The sequence pairs with the mentioned "READ_ONCE(entry->val);"
and the "val->key" check which has an address dependency.
The barrier is placed on a path executed when adding an element for
a new key. Subsequent updates targeting the same key remain unaffected.
From the user's perspective, the issue was introduced by commit
c193707dde ("tracing: Remove code which merges duplicates"), which
followed commit cbf4100efb ("tracing: Add support to detect and avoid
duplicates"). The previous code operated differently; it inherently
expected potential races which result in duplicates but merged them
later when they occurred.
Link: https://lore.kernel.org/linux-trace-kernel/20240122150928.27725-1-petr.pavlu@suse.com
Fixes: c193707dde ("tracing: Remove code which merges duplicates")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- A fix for the idle and iowait time accounting vs. CPU hotplug.
The time is reset on CPU hotplug which makes the accumulated
systemwide time jump backwards.
- Assorted fixes and improvements for clocksource/event drivers
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Merge tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
"Updates for time and clocksources:
- A fix for the idle and iowait time accounting vs CPU hotplug.
The time is reset on CPU hotplug which makes the accumulated
systemwide time jump backwards.
- Assorted fixes and improvements for clocksource/event drivers"
* tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug
clocksource/drivers/ep93xx: Fix error handling during probe
clocksource/drivers/cadence-ttc: Fix some kernel-doc warnings
clocksource/drivers/timer-ti-dm: Fix make W=n kerneldoc warnings
clocksource/timer-riscv: Add riscv_clock_shutdown callback
dt-bindings: timer: Add StarFive JH8100 clint
dt-bindings: timer: thead,c900-aclint-mtimer: separate mtime and mtimecmp regs
When offlining and onlining CPUs the overall reported idle and iowait
times as reported by /proc/stat jump backward and forward:
cpu 132 0 176 225249 47 6 6 21 0 0
cpu0 80 0 115 112575 33 3 4 18 0 0
cpu1 52 0 60 112673 13 3 1 2 0 0
cpu 133 0 177 226681 47 6 6 21 0 0
cpu0 80 0 116 113387 33 3 4 18 0 0
cpu 133 0 178 114431 33 6 6 21 0 0 <---- jump backward
cpu0 80 0 116 114247 33 3 4 18 0 0
cpu1 52 0 61 183 0 3 1 2 0 0 <---- idle + iowait start with 0
cpu 133 0 178 228956 47 6 6 21 0 0 <---- jump forward
cpu0 81 0 117 114929 33 3 4 18 0 0
Reason for this is that get_idle_time() in fs/proc/stat.c has different
sources for both values depending on if a CPU is online or offline:
- if a CPU is online the values may be taken from its per cpu
tick_cpu_sched structure
- if a CPU is offline the values are taken from its per cpu cpustat
structure
The problem is that the per cpu tick_cpu_sched structure is set to zero on
CPU offline. See tick_cancel_sched_timer() in kernel/time/tick-sched.c.
Therefore when a CPU is brought offline and online afterwards both its idle
and iowait sleeptime will be zero, causing a jump backward in total system
idle and iowait sleeptime. In a similar way if a CPU is then brought
offline again the total idle and iowait sleeptimes will jump forward.
It looks like this behavior was introduced with commit 4b0c0f294f
("tick: Cleanup NOHZ per cpu data on cpu down").
This was only noticed now on s390, since we switched to generic idle time
reporting with commit be76ea6144 ("s390/idle: remove arch_cpu_idle_time()
and corresponding code").
Fix this by preserving the values of idle_sleeptime and iowait_sleeptime
members of the per-cpu tick_sched structure on CPU hotplug.
Fixes: 4b0c0f294f ("tick: Cleanup NOHZ per cpu data on cpu down")
Reported-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240115163555.1004144-1-hca@linux.ibm.com
Kent Overstreet