linux-stable/kernel
Namhyung Kim 6c4f243b58 bpf: Adjust BPF stack helper functions to accommodate skip > 0
commit ee2a098851 upstream.

Let's say that the caller has storage for num_elem stack frames.  Then,
the BPF stack helper functions walk the stack for only num_elem frames.
This means that if skip > 0, one keeps only 'num_elem - skip' frames.

This is because it sets init_nr in the perf_callchain_entry to the end
of the buffer to save num_elem entries only.  I believe it was because
the perf callchain code unwound the stack frames until it reached the
global max size (sysctl_perf_event_max_stack).

However it now has perf_callchain_entry_ctx.max_stack to limit the
iteration locally.  This simplifies the code to handle init_nr in the
BPF callstack entries and removes the confusion with the perf_event's
__PERF_SAMPLE_CALLCHAIN_EARLY which sets init_nr to 0.

Also change the comment on bpf_get_stack() in the header file to be
more explicit what the return value means.

Fixes: c195651e56 ("bpf: add bpf_get_stack helper")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/30a7b5d5-6726-1cc2-eaee-8da2828a9a9c@oracle.com
Link: https://lore.kernel.org/bpf/20220314182042.71025-1-namhyung@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Based-on-patch-by: Eugene Loh <eugene.loh@oracle.com>
2022-04-08 13:59:00 +02:00
..
bpf bpf: Adjust BPF stack helper functions to accommodate skip > 0 2022-04-08 13:59:00 +02:00
cgroup Merge branch 'for-5.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2022-02-22 16:14:35 -08:00
configs configs/debug: restore DEBUG_INFO=y for overriding 2022-03-17 11:02:13 -07:00
debug kdb: Fix the putarea helper function 2022-04-08 13:58:32 +02:00
dma Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE"" 2022-04-08 13:58:59 +02:00
entry entry: Snapshot thread flags 2021-12-01 00:06:43 +01:00
events perf/core: Fix address filter parser for multiple filters 2022-04-08 13:57:39 +02:00
futex Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2022-01-17 05:49:30 +02:00
gcov gcov: Remove compiler version check 2021-12-02 17:25:21 +09:00
irq proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
kcsan KCSAN updates for v5.17 2022-01-11 09:51:26 -08:00
livepatch livepatch: Fix build failure on 32 bits processors 2022-04-08 13:58:03 +02:00
locking locking/lockdep: Iterate lock_classes directly when reading lockdep files 2022-04-08 13:58:39 +02:00
power PM: suspend: fix return value of __setup handler 2022-04-08 13:57:36 +02:00
printk printk: fix return value of printk.devkmsg __setup handler 2022-04-08 13:57:50 +02:00
rcu rcu: Mark writes to the rcu_segcblist structure's ->flags field 2022-04-08 13:58:36 +02:00
sched sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race 2022-04-08 13:57:40 +02:00
time bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
trace tracing: Have type enum modifications copy the strings 2022-04-08 13:58:59 +02:00
.gitignore
acct.c kernel: remove spurious blkdev.h includes 2021-10-18 06:17:01 -06:00
async.c Revert "module, async: async_synchronize_full() on module init iff async is used" 2022-02-03 11:20:34 -08:00
audit.c audit: improve audit queue handling when "audit=1" on cmdline 2022-01-25 13:22:51 -05:00
audit.h audit: log AUDIT_TIME_* records only from rules 2022-04-08 13:57:35 +02:00
audit_fsnotify.c fsnotify: clarify contract for create event hooks 2021-10-27 12:32:34 +02:00
audit_tree.c audit: use struct_size() helper in kmalloc() 2021-12-14 17:39:42 -05:00
audit_watch.c \n 2021-11-06 16:43:20 -07:00
auditfilter.c audit/stable-5.17 PR 20220110 2022-01-11 13:08:21 -08:00
auditsc.c audit: log AUDIT_TIME_* records only from rules 2022-04-08 13:57:35 +02:00
backtracetest.c
bounds.c
capability.c
cfi.c
compat.c
configs.c
context_tracking.c
cpu.c sched/scs: Reset task stack state in bringup_cpu() 2021-11-24 12:20:27 +01:00
cpu_pm.c
crash_core.c kernel/crash_core: suppress unknown crashkernel parameter warning 2021-12-25 12:20:55 -08:00
crash_dump.c
cred.c ucounts: Base set_cred_ucounts changes on the real user 2022-02-17 09:11:02 -06:00
delayacct.c delayacct: track delays from memory compact 2022-01-20 08:52:55 +02:00
dma.c
exec_domain.c
exit.c exit: Fix the exit_code for wait_task_zombie 2022-01-08 12:43:57 -06:00
extable.c extable: use is_kernel_text() helper 2021-11-09 10:02:51 -08:00
fail_function.c
fork.c mm: refactor vm_area_struct::anon_vma_name usage code 2022-03-05 11:08:32 -08:00
freezer.c
gen_kheaders.sh
groups.c
hung_task.c hung_task: move hung_task sysctl interface to hung_task.c 2022-01-22 08:33:34 +02:00
iomem.c
irq_work.c irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT 2021-10-15 11:25:18 +02:00
jump_label.c
kallsyms.c Livepatching changes for 5.17 2022-01-16 10:08:13 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt preempt: Restore preemption model selection configs 2021-11-11 13:09:33 +01:00
kcov.c kcov: replace local_irq_save() with a local_lock_t 2021-11-09 10:02:52 -08:00
kexec.c
kexec_core.c exit: Move oops specific logic from do_exit into make_task_dead 2021-12-13 12:04:45 -06:00
kexec_elf.c
kexec_file.c memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED 2021-11-06 13:30:42 -07:00
kexec_internal.h
kheaders.c
kmod.c
kprobes.c kprobe: move sysctl_kprobes_optimization to kprobes.c 2022-01-22 08:33:36 +02:00
ksysfs.c
kthread.c Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
latencytop.c
Makefile module: add in-kernel support for decompressing 2022-01-11 18:45:02 -08:00
module-internal.h module: add in-kernel support for decompressing 2022-01-11 18:45:02 -08:00
module.c Revert "module, async: async_synchronize_full() on module init iff async is used" 2022-02-03 11:20:34 -08:00
module_decompress.c module: fix building with sysfs disabled 2022-02-16 12:51:32 -08:00
module_signature.c
module_signing.c
notifier.c notifier: Return an error when a callback has already been registered 2021-12-29 10:37:33 +01:00
nsproxy.c
padata.c
panic.c panic: remove oops_id 2022-01-20 08:52:55 +02:00
params.c kobject: remove kset from struct kset_uevent_ops callbacks 2021-12-28 11:26:18 +01:00
pid.c pid: add pidfd_get_task() helper 2021-10-14 13:29:18 +02:00
pid_namespace.c
profile.c exit: Remove profile_handoff_task 2022-01-08 12:43:57 -06:00
ptrace.c ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE 2022-04-08 13:57:16 +02:00
range.c
reboot.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2021-11-12 11:53:16 -08:00
regset.c
relay.c
resource.c kernel/resource: fix kfree() of bootmem memory again 2022-04-08 13:58:23 +02:00
resource_kunit.c
rseq.c rseq: Remove broken uapi field layout on 32-bit little endian 2022-04-08 13:57:39 +02:00
scftorture.c scftorture: Always log error message 2021-12-07 16:36:17 -08:00
scs.c scs: Release kasan vmalloc poison in scs_free process 2021-09-30 09:37:27 +01:00
seccomp.c seccomp: Invalidate seccomp mode to catch death failures 2022-02-10 19:09:12 -08:00
signal.c signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE 2022-02-10 19:08:54 -08:00
smp.c sched: Improve wake_up_all_idle_cpus() take #2 2021-10-22 15:32:46 +02:00
smpboot.c
smpboot.h
softirq.c timers/nohz: Last resort update jiffies on nohz_full IRQ entry 2021-12-02 15:07:22 +01:00
stackleak.c gcc-plugins/stackleak: Use noinstr in favor of notrace 2022-02-03 17:02:21 -08:00
stacktrace.c stacktrace: move filter_irq_stacks() to kernel/stacktrace.c 2021-11-06 13:30:43 -07:00
static_call.c
stop_machine.c
sys.c mm: refactor vm_area_struct::anon_vma_name usage code 2022-03-05 11:08:32 -08:00
sys_ni.c mm/mempolicy: wire up syscall set_mempolicy_home_node 2022-01-15 16:30:30 +02:00
sysctl-test.c
sysctl.c x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting 2022-02-21 10:21:47 +01:00
task_work.c
taskstats.c
torture.c locktorture,rcutorture,torture: Always log error message 2021-12-07 16:36:17 -08:00
tracepoint.c
tsacct.c taskstats: Cleanup the use of task->exit_code 2022-01-08 12:43:57 -06:00
ucount.c ucounts: Handle wrapping in is_ucounts_overlimit 2022-02-17 09:11:57 -06:00
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c
user_namespace.c ucounts: Fix systemd LimitNPROC with private users regression 2022-02-25 10:40:14 -06:00
usermode_driver.c
utsname.c
utsname_sysctl.c
watch_queue.c watch_queue: Free the page array when watch_queue is dismantled 2022-04-08 13:58:56 +02:00
watchdog.c watchdog: move watchdog sysctl interface to watchdog.c 2022-01-22 08:33:34 +02:00
watchdog_hld.c
workqueue.c Merge branch 'workqueue/for-5.16-fixes' into workqueue/for-5.17 2022-01-10 07:54:04 -10:00
workqueue_internal.h