diff options
author | Peter Zijlstra <[email protected]> | 2019-05-29 14:37:24 +0200 |
---|---|---|
committer | Ingo Molnar <[email protected]> | 2019-06-17 12:11:58 +0200 |
commit | 085ebfe937d7a7a5df1729f35a12d6d655fea68c (patch) | |
tree | 72d555ef2b2430160f96de4b2ab868d5783855f0 | |
parent | 9e0babf2c06c73cda2c0cd37a1653d823adb40ec (diff) |
perf/core: Fix perf_sample_regs_user() mm check
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 <[email protected]>
Reported-by: Young Xiao <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Will Deacon <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 4018994f3d87 ("perf: Add ability to attach user level registers dump to sample")
Signed-off-by: Ingo Molnar <[email protected]>
-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 abbd4b3b96c2..2e32faac5511 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5923,7 +5923,7 @@ static void perf_sample_regs_user(struct perf_regs *regs_user, if (user_mode(regs)) { regs_user->abi = perf_reg_abi(current); regs_user->regs = regs; - } else if (current->mm) { + } else if (!(current->flags & PF_KTHREAD)) { perf_get_regs_user(regs_user, regs, regs_user_copy); } else { regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; |