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authorMichael Ellerman <michael@ellerman.id.au>2007-09-11 15:23:51 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-09-11 17:21:20 -0700
commit3210f0ecdba6a81c3f8efe6f442d2e1f57db98f9 (patch)
treee7f928376db3d0c72413760fe2232b9a50fa08b1 /kernel
parentf629307c857c030d5a3dd777fee37c8bb395e171 (diff)
downloadlinux-linaro-3210f0ecdba6a81c3f8efe6f442d2e1f57db98f9.tar.gz
Restore call_usermodehelper_pipe() behaviour
The semantics of call_usermodehelper_pipe() used to be that it would fork the helper, and wait for the kernel thread to be started. This was implemented by setting sub_info.wait to 0 (implicitly), and doing a wait_for_completion(). As part of the cleanup done in 0ab4dc92278a0f3816e486d6350c6652a72e06c8, call_usermodehelper_pipe() was changed to pass 1 as the value for wait to call_usermodehelper_exec(). This is equivalent to setting sub_info.wait to 1, which is a change from the previous behaviour. Using 1 instead of 0 causes __call_usermodehelper() to start the kernel thread running wait_for_helper(), rather than directly calling ____call_usermodehelper(). The end result is that the calling kernel code blocks until the user mode helper finishes. As the helper is expecting input on stdin, and now no one is writing anything, everything locks up (observed in do_coredump). The fix is to change the 1 to UMH_WAIT_EXEC (aka 0), indicating that we want to wait for the kernel thread to be started, but not for the helper to finish. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kmod.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 9809cc1f33d..c6a4f8aebeb 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -505,7 +505,7 @@ int call_usermodehelper_pipe(char *path, char **argv, char **envp,
if (ret < 0)
goto out;
- return call_usermodehelper_exec(sub_info, 1);
+ return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
out:
call_usermodehelper_freeinfo(sub_info);