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authorPeter Zijlstra <[email protected]>2019-05-29 14:37:24 +0200
committerIngo Molnar <[email protected]>2019-06-17 12:11:58 +0200
commit085ebfe937d7a7a5df1729f35a12d6d655fea68c (patch)
tree72d555ef2b2430160f96de4b2ab868d5783855f0
parent9e0babf2c06c73cda2c0cd37a1653d823adb40ec (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.c2
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;