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authorMichal Hocko <mhocko@suse.com>2016-05-23 16:26:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-23 17:04:14 -0700
commit598fdc1d66674264e122ca9d007ad822e98d8b8d (patch)
tree7bfc47b990ddbe11aa324e74fde24676fc202517
parent17b0573d77fbd547cbf1d711b90d269bdcc1efd3 (diff)
downloadlinux-598fdc1d66674264e122ca9d007ad822e98d8b8d.tar.gz
uprobes: wait for mmap_sem for write killable
xol_add_vma needs mmap_sem for write. If the waiting task gets killed by the oom killer it would block oom_reaper from asynchronous address space reclaim and reduce the chances of timely OOM resolving. Wait for the lock in the killable mode and return with EINTR if the task got killed while waiting. Do not warn in dup_xol_work if __create_xol_area failed due to fatal signal pending because this is usually considered a kernel issue. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/events/uprobes.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c01f733ff2e1..b7a525ab2083 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1130,7 +1130,9 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
struct vm_area_struct *vma;
int ret;
- down_write(&mm->mmap_sem);
+ if (down_write_killable(&mm->mmap_sem))
+ return -EINTR;
+
if (mm->uprobes_state.xol_area) {
ret = -EALREADY;
goto fail;
@@ -1469,7 +1471,8 @@ static void dup_xol_work(struct callback_head *work)
if (current->flags & PF_EXITING)
return;
- if (!__create_xol_area(current->utask->dup_xol_addr))
+ if (!__create_xol_area(current->utask->dup_xol_addr) &&
+ !fatal_signal_pending(current))
uprobe_warn(current, "dup xol area");
}