diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2010-05-26 14:43:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-27 09:12:45 -0700 |
| commit | 269b005a28e124a341df4adef2c3661cf7371fcc (patch) | |
| tree | 226b105cc4c1bbe0b3fe92f2733708a7dc2dedb8 | |
| parent | 5e43aef530ba39206f7923295388f7ec3c5a7d93 (diff) | |
coredump: shift down_write(mmap_sem) into coredump_wait()
- move the cprm.mm_flags checks up, before we take mmap_sem
- move down_write(mmap_sem) and ->core_state check from do_coredump()
to coredump_wait()
This simplifies the code and makes the locking symmetrical.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/exec.c | 19 |
1 files changed, 7 insertions, 12 deletions
diff --git a/fs/exec.c b/fs/exec.c index 6501823b7a1b..0c72d23ed0e2 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1662,12 +1662,15 @@ static int coredump_wait(int exit_code, struct core_state *core_state) struct task_struct *tsk = current; struct mm_struct *mm = tsk->mm; struct completion *vfork_done; - int core_waiters; + int core_waiters = -EBUSY; init_completion(&core_state->startup); core_state->dumper.task = tsk; core_state->dumper.next = NULL; - core_waiters = zap_threads(tsk, mm, core_state, exit_code); + + down_write(&mm->mmap_sem); + if (!mm->core_state) + core_waiters = zap_threads(tsk, mm, core_state, exit_code); up_write(&mm->mmap_sem); if (unlikely(core_waiters < 0)) @@ -1860,20 +1863,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) binfmt = mm->binfmt; if (!binfmt || !binfmt->core_dump) goto fail; + if (!__get_dumpable(cprm.mm_flags)) + goto fail; cred = prepare_creds(); if (!cred) goto fail; - - down_write(&mm->mmap_sem); - /* - * If another thread got here first, or we are not dumpable, bail out. - */ - if (mm->core_state || !__get_dumpable(cprm.mm_flags)) { - up_write(&mm->mmap_sem); - goto fail_creds; - } - /* * We cannot trust fsuid as being the "true" uid of the * process nor do we know its entire history. We only know it |