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authorMichal Hocko <mhocko@suse.com>2016-05-23 16:26:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-23 17:04:14 -0700
commitf268dfe905d4682150d4acbb25f59adc04cd9398 (patch)
treefe801df15a0b82af4ac665bfa92db7804c06f9b5
parent013373e8b86735086ac86aff782637f7e58ff84d (diff)
downloadlinux-f268dfe905d4682150d4acbb25f59adc04cd9398.tar.gz
exec: make exec path waiting for mmap_sem killable
setup_arg_pages requires 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. All the callers are already handling error path and the fatal signal doesn't need any additional treatment. The same applies to __bprm_mm_init. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/exec.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 4f079bd083af..887c1c955df8 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -263,7 +263,10 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
if (!vma)
return -ENOMEM;
- down_write(&mm->mmap_sem);
+ if (down_write_killable(&mm->mmap_sem)) {
+ err = -EINTR;
+ goto err_free;
+ }
vma->vm_mm = mm;
/*
@@ -290,6 +293,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
return 0;
err:
up_write(&mm->mmap_sem);
+err_free:
bprm->vma = NULL;
kmem_cache_free(vm_area_cachep, vma);
return err;
@@ -696,7 +700,9 @@ int setup_arg_pages(struct linux_binprm *bprm,
bprm->loader -= stack_shift;
bprm->exec -= stack_shift;
- down_write(&mm->mmap_sem);
+ if (down_write_killable(&mm->mmap_sem))
+ return -EINTR;
+
vm_flags = VM_STACK_FLAGS;
/*