This is a note to let you know that I've just added the patch titled
blktrace: fix trace mutex deadlock
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
blktrace-fix-trace-mutex-deadlock.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue 12 May 2020 06:12:56 PM CEST
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Sun, 19 Nov 2017 11:52:55 -0700
Subject: blktrace: fix trace mutex deadlock
From: Jens Axboe <axboe@xxxxxxxxx>
commit 2967acbb257a6a9bf912f4778b727e00972eac9b upstream.
A previous commit changed the locking around registration/cleanup,
but direct callers of blk_trace_remove() were missed. This means
that if we hit the error path in setup, we will deadlock on
attempting to re-acquire the queue trace mutex.
Fixes: 1f2cac107c59 ("blktrace: fix unlocked access to init/start-stop/teardown")
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/blktrace.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -591,7 +591,7 @@ static int __blk_trace_setup(struct requ
return ret;
if (copy_to_user(arg, &buts, sizeof(buts))) {
- blk_trace_remove(q);
+ __blk_trace_remove(q);
return -EFAULT;
}
return 0;
@@ -637,7 +637,7 @@ static int compat_blk_trace_setup(struct
return ret;
if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
- blk_trace_remove(q);
+ __blk_trace_remove(q);
return -EFAULT;
}
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-4.14/blktrace-fix-unlocked-access-to-init-start-stop-teardown.patch
queue-4.14/blktrace-protect-q-blk_trace-with-rcu.patch
queue-4.14/blktrace-fix-trace-mutex-deadlock.patch
queue-4.14/blktrace-fix-dereference-after-null-check.patch
