forked from Minki/linux
498f6650ae
Initialize the request queue lock earlier such that the following race can no longer occur: blk_init_queue_node() blkcg_print_blkgs() blk_alloc_queue_node (1) q->queue_lock = &q->__queue_lock (2) blkcg_init_queue(q) (3) spin_lock_irq(blkg->q->queue_lock) (4) q->queue_lock = lock (5) spin_unlock_irq(blkg->q->queue_lock) (6) (1) allocate an uninitialized queue; (2) initialize queue_lock to its default internal lock; (3) initialize blkcg part of request queue, which will create blkg and then insert it to blkg_list; (4) traverse blkg_list and find the created blkg, and then take its queue lock, here it is the default *internal lock*; (5) *race window*, now queue_lock is overridden with *driver specified lock*; (6) now unlock *driver specified lock*, not the locked *internal lock*, unlock balance breaks. The changes in this patch are as follows: - Move the .queue_lock initialization from blk_init_queue_node() into blk_alloc_queue_node(). - Only override the .queue_lock pointer for legacy queues because it is not useful for blk-mq queues to override this pointer. - For all all block drivers that initialize .queue_lock explicitly, change the blk_alloc_queue() call in the driver into a blk_alloc_queue_node() call and remove the explicit .queue_lock initialization. Additionally, initialize the spin lock that will be used as queue lock earlier if necessary. Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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aoe | ||
drbd | ||
mtip32xx | ||
paride | ||
rsxx | ||
xen-blkback | ||
zram | ||
amiflop.c | ||
ataflop.c | ||
brd.c | ||
cryptoloop.c | ||
DAC960.c | ||
DAC960.h | ||
floppy.c | ||
Kconfig | ||
loop.c | ||
loop.h | ||
Makefile | ||
nbd.c | ||
null_blk.c | ||
pktcdvd.c | ||
ps3disk.c | ||
ps3vram.c | ||
rbd_types.h | ||
rbd.c | ||
skd_main.c | ||
skd_s1120.h | ||
sunvdc.c | ||
swim3.c | ||
swim_asm.S | ||
swim.c | ||
sx8.c | ||
umem.c | ||
umem.h | ||
virtio_blk.c | ||
xen-blkfront.c | ||
xsysace.c | ||
z2ram.c |