Re: [syzbot] [block?] [trace?] INFO: task hung in blk_trace_ioctl
From: syzbot
Date: Fri Dec 01 2023 - 21:15:03 EST
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Subject: [block?] [trace?] INFO: task hung in blk_trace_ioctl
Author: eadavis@xxxxxx
please test task hung in blk_trace_ioctl
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 8c9660f65153
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 54ade89a1ad2..a1b341722693 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -735,7 +735,10 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
int ret, start = 0;
char b[BDEVNAME_SIZE];
- mutex_lock(&q->debugfs_mutex);
+ if (cmd == BLKTRACESETUP)
+ mutex_lock_nested(&q->debugfs_mutex, 0);
+ else
+ mutex_lock_nested(&q->debugfs_mutex, 1);
switch (cmd) {
case BLKTRACESETUP: