This is a note to let you know that I've just added the patch titled blktrace: fix unlocked access to init/start-stop/teardown to the 4.4-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-unlocked-access-to-init-start-stop-tear.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit bf5b9cf66d2ef05afd456e3b524edc72d1ae1452 Author: Jens Axboe <axboe@xxxxxxxxx> Date: Sun Nov 5 09:13:48 2017 -0700 blktrace: fix unlocked access to init/start-stop/teardown 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@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 5e6fc28414028..dc5fd20429d8e 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -323,7 +323,7 @@ static void blk_trace_cleanup(struct blk_trace *bt) put_probe_ref(); } -int blk_trace_remove(struct request_queue *q) +static int __blk_trace_remove(struct request_queue *q) { struct blk_trace *bt; @@ -336,6 +336,17 @@ int blk_trace_remove(struct request_queue *q) 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, @@ -546,9 +557,8 @@ 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; @@ -567,6 +577,19 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, } 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) @@ -603,7 +626,7 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name, } #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; @@ -642,6 +665,17 @@ int blk_trace_startstop(struct request_queue *q, int start) 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); /* @@ -672,7 +706,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 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: @@ -683,10 +717,10 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 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; @@ -704,10 +738,14 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) **/ 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); } /*