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| author | Peter Zijlstra <peterz@infradead.org> | 2019-05-29 14:37:24 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-10-05 16:20:01 +0100 |
| commit | aaeeb3e68968a22bfc42c98d1fc1f1ed48b79a45 (patch) | |
| tree | 70136a751dbbd8de286a44e18093102459abd331 /kernel/events | |
| parent | 1bad37d8251ba2c47ad91913a8a51f52ffe2874b (diff) | |
| download | linux-stable-aaeeb3e68968a22bfc42c98d1fc1f1ed48b79a45.tar.gz linux-stable-aaeeb3e68968a22bfc42c98d1fc1f1ed48b79a45.tar.bz2 linux-stable-aaeeb3e68968a22bfc42c98d1fc1f1ed48b79a45.zip | |
perf/core: Fix perf_sample_regs_user() mm check
commit 085ebfe937d7a7a5df1729f35a12d6d655fea68c upstream.
perf_sample_regs_user() uses 'current->mm' to test for the presence of
userspace, but this is insufficient, consider use_mm().
A better test is: '!(current->flags & PF_KTHREAD)', exec() clears
PF_KTHREAD after it sets the new ->mm but before it drops to userspace
for the first time.
Possibly obsoletes: bf05fc25f268 ("powerpc/perf: Fix oops when kthread execs user process")
Reported-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reported-by: Young Xiao <92siuyang@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4018994f3d87 ("perf: Add ability to attach user level registers dump to sample")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 3beed0ea98d9..b4c6887bdf5c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4581,7 +4581,7 @@ static void perf_sample_regs_user(struct perf_regs_user *regs_user, struct pt_regs *regs) { if (!user_mode(regs)) { - if (current->mm) + if (!(current->flags & PF_KTHREAD)) regs = task_pt_regs(current); else regs = NULL; |