[PATCH] coredump: Avoid fs freezing deadlock when dumping core

[Jan Kara]

Commit 2507a4fbd48a96bc4236e584252635f8539079df (make dump_emit() use
vfs_write() instead of banging at ->f_op->write directly) introduced a
possible deadlock when dumping core while filesystem is being frozen. We
already acquired freeze protection in do_coredump() and after this patch
we also acquire it in vfs_write(). Fix the problem by removing now
unnecessary protection in do_coredump().

Fixes: 2507a4fbd48a96bc4236e584252635f8539079df
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 fs/coredump.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/coredump.c b/fs/coredump.c
index 62406b6959b6..bdb9052744d8 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -657,11 +657,8 @@ void do_coredump(const siginfo_t *siginfo)
 		goto close_fail;
 	if (displaced)
 		put_files_struct(displaced);
-	if (!dump_interrupted()) {
-		file_start_write(cprm.file);
+	if (!dump_interrupted())
 		core_dumped = binfmt->core_dump(&cprm);
-		file_end_write(cprm.file);
-	}
 	if (ispipe && core_pipe_limit)
 		wait_for_dump_helpers(cprm.file);
 close_fail:
-- 
1.8.1.4


--liOOAslEiF7prFVr--
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