From: Jens Axboe axboe@kernel.dk
commit 1f2cac107c591c24b60b115d6050adc213d10fc0 upstream.
sg.c calls into the blktrace functions without holding the proper queue mutex for doing setup, start/stop, or teardown.
Add internal unlocked variants, and export the ones that do the proper locking.
Fixes: 6da127ad0918 ("blktrace: Add blktrace ioctls to SCSI generic devices") Tested-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/blktrace.c | 58 +++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 48 insertions(+), 10 deletions(-)
--- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -352,7 +352,7 @@ static void blk_trace_cleanup(struct blk put_probe_ref(); }
-int blk_trace_remove(struct request_queue *q) +static int __blk_trace_remove(struct request_queue *q) { struct blk_trace *bt;
@@ -365,6 +365,17 @@ int blk_trace_remove(struct request_queu
return 0; } + +int blk_trace_remove(struct request_queue *q) +{ + int ret; + + mutex_lock(&q->blk_trace_mutex); + ret = __blk_trace_remove(q); + mutex_unlock(&q->blk_trace_mutex); + + return ret; +} EXPORT_SYMBOL_GPL(blk_trace_remove);
static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, @@ -565,9 +576,8 @@ err: return ret; }
-int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, - struct block_device *bdev, - char __user *arg) +static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev, + struct block_device *bdev, char __user *arg) { struct blk_user_trace_setup buts; int ret; @@ -586,6 +596,19 @@ int blk_trace_setup(struct request_queue } return 0; } + +int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, + struct block_device *bdev, + char __user *arg) +{ + int ret; + + mutex_lock(&q->blk_trace_mutex); + ret = __blk_trace_setup(q, name, dev, bdev, arg); + mutex_unlock(&q->blk_trace_mutex); + + return ret; +} EXPORT_SYMBOL_GPL(blk_trace_setup);
#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) @@ -622,7 +645,7 @@ static int compat_blk_trace_setup(struct } #endif
-int blk_trace_startstop(struct request_queue *q, int start) +static int __blk_trace_startstop(struct request_queue *q, int start) { int ret; struct blk_trace *bt = q->blk_trace; @@ -661,6 +684,17 @@ int blk_trace_startstop(struct request_q
return ret; } + +int blk_trace_startstop(struct request_queue *q, int start) +{ + int ret; + + mutex_lock(&q->blk_trace_mutex); + ret = __blk_trace_startstop(q, start); + mutex_unlock(&q->blk_trace_mutex); + + return ret; +} EXPORT_SYMBOL_GPL(blk_trace_startstop);
/* @@ -691,7 +725,7 @@ int blk_trace_ioctl(struct block_device switch (cmd) { case BLKTRACESETUP: bdevname(bdev, b); - ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); + ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); break; #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) case BLKTRACESETUP32: @@ -702,10 +736,10 @@ int blk_trace_ioctl(struct block_device case BLKTRACESTART: start = 1; case BLKTRACESTOP: - ret = blk_trace_startstop(q, start); + ret = __blk_trace_startstop(q, start); break; case BLKTRACETEARDOWN: - ret = blk_trace_remove(q); + ret = __blk_trace_remove(q); break; default: ret = -ENOTTY; @@ -723,10 +757,14 @@ int blk_trace_ioctl(struct block_device **/ void blk_trace_shutdown(struct request_queue *q) { + mutex_lock(&q->blk_trace_mutex); + if (q->blk_trace) { - blk_trace_startstop(q, 0); - blk_trace_remove(q); + __blk_trace_startstop(q, 0); + __blk_trace_remove(q); } + + mutex_unlock(&q->blk_trace_mutex); }
#ifdef CONFIG_BLK_CGROUP