In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_interruptible. This is needed for perf_event_open to be
converted (with no semantic changes) from working on a mutex to
wroking on a rwsem.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87k0tybqfy.fsf@x220.int.ebiederm.org
In preparation for converting exec_update_mutex to a rwsem so that
multiple readers can execute in parallel and not deadlock, add
down_read_killable_nested. This is needed so that kcmp_lock
can be converted from working on a mutexes to working on rw_semaphores.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/87o8jabqh3.fsf@x220.int.ebiederm.org
Changeset cd8084f91c ("locking/lockdep: Apply crossrelease to completions")
added a CONFIG_LOCKDEP_COMPLETE (that was later renamed to
CONFIG_LOCKDEP_COMPLETIONS).
Such changeset renamed the init_completion, and add a macro
that would either run a modified version or the original code.
However, such code reported too many false positives. So, it
ended being dropped later on by
changeset e966eaeeb6 ("locking/lockdep: Remove the cross-release locking checks").
Yet, the define remained there as just:
#define init_completion(x) __init_completion(x)
Get rid of the define, and return __init_completion() function
to its original name.
Fixes: e966eaeeb6 ("locking/lockdep: Remove the cross-release locking checks")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/e657bfc533545c185b1c3c55926a449ead56a88b.1606823973.git.mchehab+huawei@kernel.org
The selftest nests rwlock_t inside raw_spinlock_t, this is invalid.
Reported-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
When building with W=2, there is a flood of warnings about the seqlock
macros shadowing local variables:
19806 linux/seqlock.h:331:11: warning: declaration of 'seq' shadows a previous local [-Wshadow]
48 linux/seqlock.h:348:11: warning: declaration of 'seq' shadows a previous local [-Wshadow]
8 linux/seqlock.h:379:11: warning: declaration of 'seq' shadows a previous local [-Wshadow]
Prefix the local variables to make the warning useful elsewhere again.
Fixes: 52ac39e5db ("seqlock: seqcount_t: Implement all read APIs as statement expressions")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201026165044.3722931-1-arnd@kernel.org
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Merge tag 'gfs2-v5.10-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 fixes from Andreas Gruenbacher:
"Various gfs2 fixes"
* tag 'gfs2-v5.10-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix deadlock between gfs2_{create_inode,inode_lookup} and delete_work_func
gfs2: Upgrade shared glocks for atime updates
gfs2: Don't freeze the file system during unmount
gfs2: check for empty rgrp tree in gfs2_ri_update
gfs2: set lockdep subclass for iopen glocks
gfs2: Fix deadlock dumping resource group glocks
- Fix numerous issues with instrumentation and exception entry
- Fix hideous typo in unused register field definition
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
"I'm sad to say that we've got an unusually large arm64 fixes pull for
rc7 which addresses numerous significant instrumentation issues with
our entry code.
Without these patches, lockdep is hopelessly unreliable in some
configurations [1,2] and syzkaller is therefore not a lot of use
because it's so noisy.
Although much of this has always been broken, it appears to have been
exposed more readily by other changes such as 044d0d6de9 ("lockdep:
Only trace IRQ edges") and general lockdep improvements around IRQ
tracing and NMIs.
Fixing this properly required moving much of the instrumentation hooks
from our entry assembly into C, which Mark has been working on for the
last few weeks. We're not quite ready to move to the recently added
generic functions yet, but the code here has been deliberately written
to mimic that closely so we can look at cleaning things up once we
have a bit more breathing room.
Having said all that, the second version of these patches was posted
last week and I pushed it into our CI (kernelci and cki) along with a
commit which forced on PROVE_LOCKING, NOHZ_FULL and
CONTEXT_TRACKING_FORCE. The result? We found a real bug in the
md/raid10 code [3].
Oh, and there's also a really silly typo patch that's unrelated.
Summary:
- Fix numerous issues with instrumentation and exception entry
- Fix hideous typo in unused register field definition"
[1] https://lore.kernel.org/r/CACT4Y+aAzoJ48Mh1wNYD17pJqyEcDnrxGfApir=-j171TnQXhw@mail.gmail.com
[2] https://lore.kernel.org/r/20201119193819.GA2601289@elver.google.com
[3] https://lore.kernel.org/r/94c76d5e-466a-bc5f-e6c2-a11b65c39f83@redhat.com
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mte: Fix typo in macro definition
arm64: entry: fix EL1 debug transitions
arm64: entry: fix NMI {user, kernel}->kernel transitions
arm64: entry: fix non-NMI kernel<->kernel transitions
arm64: ptrace: prepare for EL1 irq/rcu tracking
arm64: entry: fix non-NMI user<->kernel transitions
arm64: entry: move el1 irq/nmi logic to C
arm64: entry: prepare ret_to_user for function call
arm64: entry: move enter_from_user_mode to entry-common.c
arm64: entry: mark entry code as noinstr
arm64: mark idle code as noinstr
arm64: syscall: exit userspace before unmasking exceptions
A couple of fixes that surfaced at the last minute.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull vdpa fixes from Michael Tsirkin:
"A couple of fixes that surfaced at the last minute"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
vhost_vdpa: return -EFAULT if copy_to_user() fails
vdpa: mlx5: fix vdpa/vhost dependencies
Here are the pending sound fixes for 5.10: all small device-specific
fixes, and nothing particular stands out, so far.
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Merge tag 'sound-5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"Here are the pending sound fixes for 5.10: all small device-specific
fixes, and nothing particular stands out, so far"
* tag 'sound-5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda/realtek: Add mute LED quirk to yet another HP x360 model
ALSA: hda/realtek: Fix bass speaker DAC assignment on Asus Zephyrus G14
ALSA: hda/generic: Add option to enforce preferred_dacs pairs
ALSA: usb-audio: US16x08: fix value count for level meters
ALSA: hda/realtek - Add new codec supported for ALC897
ASoC: rt5682: change SAR voltage threshold
ASoC: wm_adsp: fix error return code in wm_adsp_load()
ALSA: hda/realtek: Enable headset of ASUS UX482EG & B9400CEA with ALC294
ASoC: qcom: Fix enabling BCLK and LRCLK in LPAIF invalid state
ALSA: hda/realtek - Fixed Dell AIO wrong sound tone
ASoC: Intel: bytcr_rt5640: Fix HP Pavilion x2 Detachable quirks
In case the bootconfig is created on one kind of endian machine, and then
read on the other kind of endian kernel, the size and checksum will be
incorrect. Instead, have both the size and checksum always be little
endian and have the tool and the kernel convert it from little endian to
or from the host endian.
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Merge tag 'trace-v5.10-rc6-bootconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull bootconfig fixes from Steven Rostedt:
"Have bootconfig size and checksum be little endian
In case the bootconfig is created on one kind of endian machine, and
then read on the other kind of endian kernel, the size and checksum
will be incorrect. Instead, have both the size and checksum always be
little endian and have the tool and the kernel convert it from little
endian to or from the host endian"
* tag 'trace-v5.10-rc6-bootconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
docs: bootconfig: Add the endianness of fields
tools/bootconfig: Store size and checksum in footer as le32
bootconfig: Load size and checksum in the footer as le32
The copy_to_user() function returns the number of bytes remaining to be
copied but this should return -EFAULT to the user.
Fixes: 1b48dc03e5 ("vhost: vdpa: report iova range")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/X8c32z5EtDsMyyIL@mwanda
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
drivers/vdpa/mlx5/ uses vhost_iotlb*() interfaces, so select
VHOST_IOTLB to make them be built.
However, if VHOST_IOTLB is the only VHOST symbol that is
set/enabled, the object file still won't be built because
drivers/Makefile won't descend into drivers/vhost/ to build it,
so make drivers/Makefile build the needed binary whenever
VHOST_IOTLB is set, like it does for VHOST_RING.
Fixes these build errors:
ERROR: modpost: "vhost_iotlb_itree_next" [drivers/vdpa/mlx5/mlx5_vdpa.ko] undefined!
ERROR: modpost: "vhost_iotlb_itree_first" [drivers/vdpa/mlx5/mlx5_vdpa.ko] undefined!
Fixes: 29064bfdab ("vdpa/mlx5: Add support library for mlx5 VDPA implementation")
Fixes: aff90770e5 ("vdpa/mlx5: Fix dependency on MLX5_CORE")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Eli Cohen <eli@mellanox.com>
Cc: Parav Pandit <parav@mellanox.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20201128213905.27409-1-rdunlap@infradead.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
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Merge tag '5.10-rc6-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs fixes from Steve French:
"Two smb3 fixes for stable"
* tag '5.10-rc6-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: fix potential use-after-free in cifs_echo_request()
cifs: allow syscalls to be restarted in __smb_send_rqst()
- Use correct timestamp variable for ring buffer write stamp update
- Fix up before stamp and write stamp when crossing ring buffer sub
buffers
- Keep a zero delta in ring buffer in slow path if cmpxchg fails
- Fix trace_printk static buffer for archs that care
- Fix ftrace record accounting for ftrace ops with trampolines
- Fix DYNAMIC_FTRACE_WITH_DIRECT_CALLS dependency
- Remove WARN_ON in hwlat tracer that triggers on something that is OK
- Make "my_tramp" trampoline in ftrace direct sample code global
- Fixes in the bootconfig tool for better alignment management
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Merge tag 'trace-v5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
- Use correct timestamp variable for ring buffer write stamp update
- Fix up before stamp and write stamp when crossing ring buffer sub
buffers
- Keep a zero delta in ring buffer in slow path if cmpxchg fails
- Fix trace_printk static buffer for archs that care
- Fix ftrace record accounting for ftrace ops with trampolines
- Fix DYNAMIC_FTRACE_WITH_DIRECT_CALLS dependency
- Remove WARN_ON in hwlat tracer that triggers on something that is OK
- Make "my_tramp" trampoline in ftrace direct sample code global
- Fixes in the bootconfig tool for better alignment management
* tag 'trace-v5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ring-buffer: Always check to put back before stamp when crossing pages
ftrace: Fix DYNAMIC_FTRACE_WITH_DIRECT_CALLS dependency
ftrace: Fix updating FTRACE_FL_TRAMP
tracing: Fix alignment of static buffer
tracing: Remove WARN_ON in start_thread()
samples/ftrace: Mark my_tramp[12]? global
ring-buffer: Set the right timestamp in the slow path of __rb_reserve_next()
ring-buffer: Update write stamp with the correct ts
docs: bootconfig: Update file format on initrd image
tools/bootconfig: Align the bootconfig applied initrd image size to 4
tools/bootconfig: Fix to check the write failure correctly
tools/bootconfig: Fix errno reference after printf()
A couple of minor fixes.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull vhost fixes from Michael Tsirkin:
"A couple of minor fixes"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
vhost-vdpa: fix page pinning leakage in error path (rework)
vringh: fix vringh_iov_push_*() documentation
vhost scsi: fix lun reset completion handling
Add a description about the endianness of the size and the checksum
fields. Those must be stored as le32 instead of u32. This will allow
us to apply bootconfig to the cross build initrd without caring
the endianness.
Link: https://lkml.kernel.org/r/160583936246.547349.10964204130590955409.stgit@devnote2
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Store the size and the checksum fields in the footer as le32
instead of u32. This will allow us to apply bootconfig to the
cross build initrd without caring the endianness.
Link: https://lkml.kernel.org/r/160583935332.547349.5897811300636587426.stgit@devnote2
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Load the size and the checksum fields in the footer as le32
instead of u32. This will allow us to apply bootconfig to the
cross build initrd without caring the endianness.
Link: https://lkml.kernel.org/r/160583934457.547349.10504070298990791074.stgit@devnote2
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The current ring buffer logic checks to see if the updating of the event
buffer was interrupted, and if it is, it will try to fix up the before stamp
with the write stamp to make them equal again. This logic is flawed, because
if it is not interrupted, the two are guaranteed to be different, as the
current event just updated the before stamp before allocation. This
guarantees that the next event (this one or another interrupting one) will
think it interrupted the time updates of a previous event and inject an
absolute time stamp to compensate.
The correct logic is to always update the timestamps when traversing to a
new sub buffer.
Cc: stable@vger.kernel.org
Fixes: a389d86f7f ("ring-buffer: Have nested events still record running time stamp")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
On powerpc, kprobe-direct.tc triggered FTRACE_WARN_ON() in
ftrace_get_addr_new() followed by the below message:
Bad trampoline accounting at: 000000004222522f (wake_up_process+0xc/0x20) (f0000001)
The set of steps leading to this involved:
- modprobe ftrace-direct-too
- enable_probe
- modprobe ftrace-direct
- rmmod ftrace-direct <-- trigger
The problem turned out to be that we were not updating flags in the
ftrace record properly. From the above message about the trampoline
accounting being bad, it can be seen that the ftrace record still has
FTRACE_FL_TRAMP set though ftrace-direct module is going away. This
happens because we are checking if any ftrace_ops has the
FTRACE_FL_TRAMP flag set _before_ updating the filter hash.
The fix for this is to look for any _other_ ftrace_ops that also needs
FTRACE_FL_TRAMP.
Link: https://lkml.kernel.org/r/56c113aa9c3e10c19144a36d9684c7882bf09af5.1606412433.git.naveen.n.rao@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Fixes: a124692b69 ("ftrace: Enable trampoline when rec count returns back to one")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
With 5.9 kernel on ARM64, I found ftrace_dump output was broken but
it had no problem with normal output "cat /sys/kernel/debug/tracing/trace".
With investigation, it seems coping the data into temporal buffer seems to
break the align binary printf expects if the static buffer is not aligned
with 4-byte. IIUC, get_arg in bstr_printf expects that args has already
right align to be decoded and seq_buf_bprintf says ``the arguments are saved
in a 32bit word array that is defined by the format string constraints``.
So if we don't keep the align under copy to temporal buffer, the output
will be broken by shifting some bytes.
This patch fixes it.
Link: https://lkml.kernel.org/r/20201125225654.1618966-1-minchan@kernel.org
Cc: <stable@vger.kernel.org>
Fixes: 8e99cf91b9 ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This patch reverts commit 978defee11 ("tracing: Do a WARN_ON()
if start_thread() in hwlat is called when thread exists")
.start hook can be legally called several times if according
tracer is stopped
screen window 1
[root@localhost ~]# echo 1 > /sys/kernel/tracing/events/kmem/kfree/enable
[root@localhost ~]# echo 1 > /sys/kernel/tracing/options/pause-on-trace
[root@localhost ~]# less -F /sys/kernel/tracing/trace
screen window 2
[root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on
0
[root@localhost ~]# echo hwlat > /sys/kernel/debug/tracing/current_tracer
[root@localhost ~]# echo 1 > /sys/kernel/debug/tracing/tracing_on
[root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on
0
[root@localhost ~]# echo 2 > /sys/kernel/debug/tracing/tracing_on
triggers warning in dmesg:
WARNING: CPU: 3 PID: 1403 at kernel/trace/trace_hwlat.c:371 hwlat_tracer_start+0xc9/0xd0
Link: https://lkml.kernel.org/r/bd4d3e70-400d-9c82-7b73-a2d695e86b58@virtuozzo.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 978defee11 ("tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
my_tramp[12]? are declared as global functions in C, but they are not
marked global in the inline assembly definition. This mismatch confuses
Clang's Control-Flow Integrity checking. Fix the definitions by adding
.globl.
Link: https://lkml.kernel.org/r/20201113183414.1446671-1-samitolvanen@google.com
Fixes: 9d907f1ae8 ("ftrace/samples: Add a sample module that implements modify_ftrace_direct()")
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In gfs2_create_inode and gfs2_inode_lookup, make sure to cancel any pending
delete work before taking the inode glock. Otherwise, gfs2_cancel_delete_work
may block waiting for delete_work_func to complete, and delete_work_func may
block trying to acquire the inode glock in gfs2_inode_lookup.
Reported-by: Alexander Aring <aahringo@redhat.com>
Fixes: a0e3cc65fa ("gfs2: Turn gl_delete into a delayed work")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This patch fixes a potential use-after-free bug in
cifs_echo_request().
For instance,
thread 1
--------
cifs_demultiplex_thread()
clean_demultiplex_info()
kfree(server)
thread 2 (workqueue)
--------
apic_timer_interrupt()
smp_apic_timer_interrupt()
irq_exit()
__do_softirq()
run_timer_softirq()
call_timer_fn()
cifs_echo_request() <- use-after-free in server ptr
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
A customer has reported that several files in their multi-threaded app
were left with size of 0 because most of the read(2) calls returned
-EINTR and they assumed no bytes were read. Obviously, they could
have fixed it by simply retrying on -EINTR.
We noticed that most of the -EINTR on read(2) were due to real-time
signals sent by glibc to process wide credential changes (SIGRT_1),
and its signal handler had been established with SA_RESTART, in which
case those calls could have been automatically restarted by the
kernel.
Let the kernel decide to whether or not restart the syscalls when
there is a signal pending in __smb_send_rqst() by returning
-ERESTARTSYS. If it can't, it will return -EINTR anyway.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
In the slow path of __rb_reserve_next() a nested event(s) can happen
between evaluating the timestamp delta of the current event and updating
write_stamp via local_cmpxchg(); in this case the delta is not valid
anymore and it should be set to 0 (same timestamp as the interrupting
event), since the event that we are currently processing is not the last
event in the buffer.
Link: https://lkml.kernel.org/r/X8IVJcp1gRE+FJCJ@xps-13-7390
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lwn.net/Articles/831207
Fixes: a389d86f7f ("ring-buffer: Have nested events still record running time stamp")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The write stamp, used to calculate deltas between events, was updated with
the stale "ts" value in the "info" structure, and not with the updated "ts"
variable. This caused the deltas between events to be inaccurate, and when
crossing into a new sub buffer, had time go backwards.
Link: https://lkml.kernel.org/r/20201124223917.795844-1-elavila@google.com
Cc: stable@vger.kernel.org
Fixes: a389d86f7f ("ring-buffer: Have nested events still record running time stamp")
Reported-by: "J. Avila" <elavila@google.com>
Tested-by: Daniel Mentz <danielmentz@google.com>
Tested-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
UL in the definition of SYS_TFSR_EL1_TF1 was misspelled causing
compilation issues when trying to implement in kernel MTE async
mode.
Fix the macro correcting the typo.
Note: MTE async mode will be introduced with a future series.
Fixes: c058b1c4a5 ("arm64: mte: system register definitions")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20201130170709.22309-1-vincenzo.frascino@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In debug_exception_enter() and debug_exception_exit() we trace hardirqs
on/off while RCU isn't guaranteed to be watching, and we don't save and
restore the hardirq state, and so may return with this having changed.
Handle this appropriately with new entry/exit helpers which do the bare
minimum to ensure this is appropriately maintained, without marking
debug exceptions as NMIs. These are placed in entry-common.c with the
other entry/exit helpers.
In future we'll want to reconsider whether some debug exceptions should
be NMIs, but this will require a significant refactoring, and for now
this should prevent issues with lockdep and RCU.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marins <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-12-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Exceptions which can be taken at (almost) any time are consdiered to be
NMIs. On arm64 that includes:
* SDEI events
* GICv3 Pseudo-NMIs
* Kernel stack overflows
* Unexpected/unhandled exceptions
... but currently debug exceptions (BRKs, breakpoints, watchpoints,
single-step) are not considered NMIs.
As these can be taken at any time, kernel features (lockdep, RCU,
ftrace) may not be in a consistent kernel state. For example, we may
take an NMI from the idle code or partway through an entry/exit path.
While nmi_enter() and nmi_exit() handle most of this state, notably they
don't save/restore the lockdep state across an NMI being taken and
handled. When interrupts are enabled and an NMI is taken, lockdep may
see interrupts become disabled within the NMI code, but not see
interrupts become enabled when returning from the NMI, leaving lockdep
believing interrupts are disabled when they are actually disabled.
The x86 code handles this in idtentry_{enter,exit}_nmi(), which will
shortly be moved to the generic entry code. As we can't use either yet,
we copy the x86 approach in arm64-specific helpers. All the NMI
entrypoints are marked as noinstr to prevent any instrumentation
handling code being invoked before the state has been corrected.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-11-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
There are periods in kernel mode when RCU is not watching and/or the
scheduler tick is disabled, but we can still take exceptions such as
interrupts. The arm64 exception handlers do not account for this, and
it's possible that RCU is not watching while an exception handler runs.
The x86/generic entry code handles this by ensuring that all (non-NMI)
kernel exception handlers call irqentry_enter() and irqentry_exit(),
which handle RCU, lockdep, and IRQ flag tracing. We can't yet move to
the generic entry code, and already hadnle the user<->kernel transitions
elsewhere, so we add new kernel<->kernel transition helpers alog the
lines of the generic entry code.
Since we now track interrupts becoming masked when an exception is
taken, local_daif_inherit() is modified to track interrupts becoming
re-enabled when the original context is inherited. To balance the
entry/exit paths, each handler masks all DAIF exceptions before
exit_to_kernel_mode().
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-10-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Exceptions from EL1 may be taken when RCU isn't watching (e.g. in idle
sequences), or when the lockdep hardirqs transiently out-of-sync with
the hardware state (e.g. in the middle of local_irq_enable()). To
correctly handle these cases, we'll need to save/restore this state
across some exceptions taken from EL1.
A series of subsequent patches will update EL1 exception handlers to
handle this. In preparation for this, and to avoid dependencies between
those patches, this patch adds two new fields to struct pt_regs so that
exception handlers can track this state.
Note that this is placed in pt_regs as some entry/exit sequences such as
el1_irq are invoked from assembly, which makes it very difficult to add
a separate structure as with the irqentry_state used by x86. We can
separate this once more of the exception logic is moved to C. While the
fields only need to be bool, they are both made u64 to keep pt_regs
16-byte aligned.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-9-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
When built with PROVE_LOCKING, NO_HZ_FULL, and CONTEXT_TRACKING_FORCE
will WARN() at boot time that interrupts are enabled when we call
context_tracking_user_enter(), despite the DAIF flags indicating that
IRQs are masked.
The problem is that we're not tracking IRQ flag changes accurately, and
so lockdep believes interrupts are enabled when they are not (and
vice-versa). We can shuffle things so to make this more accurate. For
kernel->user transitions there are a number of constraints we need to
consider:
1) When we call __context_tracking_user_enter() HW IRQs must be disabled
and lockdep must be up-to-date with this.
2) Userspace should be treated as having IRQs enabled from the PoV of
both lockdep and tracing.
3) As context_tracking_user_enter() stops RCU from watching, we cannot
use RCU after calling it.
4) IRQ flag tracing and lockdep have state that must be manipulated
before RCU is disabled.
... with similar constraints applying for user->kernel transitions, with
the ordering reversed.
The generic entry code has enter_from_user_mode() and
exit_to_user_mode() helpers to handle this. We can't use those directly,
so we add arm64 copies for now (without the instrumentation markers
which aren't used on arm64). These replace the existing user_exit() and
user_exit_irqoff() calls spread throughout handlers, and the exception
unmasking is left as-is.
Note that:
* The accounting for debug exceptions from userspace now happens in
el0_dbg() and ret_to_user(), so this is removed from
debug_exception_enter() and debug_exception_exit(). As
user_exit_irqoff() wakes RCU, the userspace-specific check is removed.
* The accounting for syscalls now happens in el0_svc(),
el0_svc_compat(), and ret_to_user(), so this is removed from
el0_svc_common(). This does not adversely affect the workaround for
erratum 1463225, as this does not depend on any of the state tracking.
* In ret_to_user() we mask interrupts with local_daif_mask(), and so we
need to inform lockdep and tracing. Here a trace_hardirqs_off() is
sufficient and safe as we have not yet exited kernel context and RCU
is usable.
* As PROVE_LOCKING selects TRACE_IRQFLAGS, the ifdeferry in entry.S only
needs to check for the latter.
* EL0 SError handling will be dealt with in a subsequent patch, as this
needs to be treated as an NMI.
Prior to this patch, booting an appropriately-configured kernel would
result in spats as below:
| DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())
| WARNING: CPU: 2 PID: 1 at kernel/locking/lockdep.c:5280 check_flags.part.54+0x1dc/0x1f0
| Modules linked in:
| CPU: 2 PID: 1 Comm: init Not tainted 5.10.0-rc3 #3
| Hardware name: linux,dummy-virt (DT)
| pstate: 804003c5 (Nzcv DAIF +PAN -UAO -TCO BTYPE=--)
| pc : check_flags.part.54+0x1dc/0x1f0
| lr : check_flags.part.54+0x1dc/0x1f0
| sp : ffff80001003bd80
| x29: ffff80001003bd80 x28: ffff66ce801e0000
| x27: 00000000ffffffff x26: 00000000000003c0
| x25: 0000000000000000 x24: ffffc31842527258
| x23: ffffc31842491368 x22: ffffc3184282d000
| x21: 0000000000000000 x20: 0000000000000001
| x19: ffffc318432ce000 x18: 0080000000000000
| x17: 0000000000000000 x16: ffffc31840f18a78
| x15: 0000000000000001 x14: ffffc3184285c810
| x13: 0000000000000001 x12: 0000000000000000
| x11: ffffc318415857a0 x10: ffffc318406614c0
| x9 : ffffc318415857a0 x8 : ffffc31841f1d000
| x7 : 647261685f706564 x6 : ffffc3183ff7c66c
| x5 : ffff66ce801e0000 x4 : 0000000000000000
| x3 : ffffc3183fe00000 x2 : ffffc31841500000
| x1 : e956dc24146b3500 x0 : 0000000000000000
| Call trace:
| check_flags.part.54+0x1dc/0x1f0
| lock_is_held_type+0x10c/0x188
| rcu_read_lock_sched_held+0x70/0x98
| __context_tracking_enter+0x310/0x350
| context_tracking_enter.part.3+0x5c/0xc8
| context_tracking_user_enter+0x6c/0x80
| finish_ret_to_user+0x2c/0x13cr
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-8-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In preparation for reworking the EL1 irq/nmi entry code, move the
existing logic to C. We no longer need the asm_nmi_enter() and
asm_nmi_exit() wrappers, so these are removed. The new C functions are
marked noinstr, which prevents compiler instrumentation and runtime
probing.
In subsequent patches we'll want the new C helpers to be called in all
cases, so we don't bother wrapping the calls with ifdeferry. Even when
the new C functions are stubs the trivial calls are unlikely to have a
measurable impact on the IRQ or NMI paths anyway.
Prototypes are added to <asm/exception.h> as otherwise (in some
configurations) GCC will complain about the lack of a forward
declaration. We already do this for existing function, e.g.
enter_from_user_mode().
The new helpers are marked as noinstr (which prevents all
instrumentation, tracing, and kprobes). Otherwise, there should be no
functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-7-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In a subsequent patch ret_to_user will need to make a C function call
(in some configurations) which may clobber x0-x18 at the start of the
finish_ret_to_user block, before enable_step_tsk consumes the flags
loaded into x1.
In preparation for this, let's load the flags into x19, which is
preserved across C function calls. This avoids a redundant reload of the
flags and ensures we operate on a consistent shapshot regardless.
There should be no functional change as a result of this patch. At this
point of the entry/exit paths we only need to preserve x28 (tsk) and the
sp, and x19 is free for this use.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-6-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In later patches we'll want to extend enter_from_user_mode() and add a
corresponding exit_to_user_mode(). As these will be common for all
entries/exits from userspace, it'd be better for these to live in
entry-common.c with the rest of the entry logic.
This patch moves enter_from_user_mode() into entry-common.c. As with
other functions in entry-common.c it is marked as noinstr (which
prevents all instrumentation, tracing, and kprobes) but there are no
other functional changes.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-5-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Functions in entry-common.c are marked as notrace and NOKPROBE_SYMBOL(),
but they're still subject to other instrumentation which may rely on
lockdep/rcu/context-tracking being up-to-date, and may cause nested
exceptions (e.g. for WARN/BUG or KASAN's use of BRK) which will corrupt
exceptions registers which have not yet been read.
Prevent this by marking all functions in entry-common.c as noinstr to
prevent compiler instrumentation. This also blacklists the functions for
tracing and kprobes, so we don't need to handle that separately.
Functions elsewhere will be dealt with in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Core code disables RCU when calling arch_cpu_idle(), so it's not safe
for arch_cpu_idle() or its calees to be instrumented, as the
instrumentation callbacks may attempt to use RCU or other features which
are unsafe to use in this context.
Mark them noinstr to prevent issues.
The use of local_irq_enable() in arch_cpu_idle() is similarly
problematic, and the "sched/idle: Fix arch_cpu_idle() vs tracing" patch
queued in the tip tree addresses that case.
Reported-by: Marco Elver <elver@google.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In el0_svc_common() we unmask exceptions before we call user_exit(), and
so there's a window where an IRQ or debug exception can be taken while
RCU is not watching. In do_debug_exception() we account for this in via
debug_exception_{enter,exit}(), but in the el1_irq asm we do not and we
call trace functions which rely on RCU before we have a guarantee that
RCU is watching.
Let's avoid this by having el0_svc_common() exit userspace before
unmasking exceptions, matching what we do for all other EL0 entry paths.
We can use user_exit_irqoff() to avoid the pointless save/restore of IRQ
flags while we're sure exceptions are masked in DAIF.
The workaround for Cortex-A76 erratum 1463225 may trigger a debug
exception before this point, but the debug code invoked in this case is
safe even when RCU is not watching.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
