From 4fd41a8552afc01054d9d9fc7f1a63c324867d27 Mon Sep 17 00:00:00 2001 From: Ken Xue Date: Tue, 1 Dec 2015 14:45:46 +0800 Subject: SCSI: Fix NULL pointer dereference in runtime PM The routines in scsi_pm.c assume that if a runtime-PM callback is invoked for a SCSI device, it can only mean that the device's driver has asked the block layer to handle the runtime power management (by calling blk_pm_runtime_init(), which among other things sets q->dev). However, this assumption turns out to be wrong for things like the ses driver. Normally ses devices are not allowed to do runtime PM, but userspace can override this setting. If this happens, the kernel gets a NULL pointer dereference when blk_post_runtime_resume() tries to use the uninitialized q->dev pointer. This patch fixes the problem by checking q->dev in block layer before handle runtime PM. Since ses doesn't define any PM callbacks and call blk_pm_runtime_init(), the crash won't occur. This fixes Bugzilla #101371. https://bugzilla.kernel.org/show_bug.cgi?id=101371 More discussion can be found from below link. http://marc.info/?l=linux-scsi&m=144163730531875&w=2 Signed-off-by: Ken Xue Acked-by: Alan Stern Cc: Xiangliang Yu Cc: James E.J. Bottomley Cc: Jens Axboe Cc: Michael Terry Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe --- block/blk-core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index a0af4043dda2..3636be469fa2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -3405,6 +3405,9 @@ int blk_pre_runtime_suspend(struct request_queue *q) { int ret = 0; + if (!q->dev) + return ret; + spin_lock_irq(q->queue_lock); if (q->nr_pending) { ret = -EBUSY; @@ -3432,6 +3435,9 @@ EXPORT_SYMBOL(blk_pre_runtime_suspend); */ void blk_post_runtime_suspend(struct request_queue *q, int err) { + if (!q->dev) + return; + spin_lock_irq(q->queue_lock); if (!err) { q->rpm_status = RPM_SUSPENDED; @@ -3456,6 +3462,9 @@ EXPORT_SYMBOL(blk_post_runtime_suspend); */ void blk_pre_runtime_resume(struct request_queue *q) { + if (!q->dev) + return; + spin_lock_irq(q->queue_lock); q->rpm_status = RPM_RESUMING; spin_unlock_irq(q->queue_lock); @@ -3478,6 +3487,9 @@ EXPORT_SYMBOL(blk_pre_runtime_resume); */ void blk_post_runtime_resume(struct request_queue *q, int err) { + if (!q->dev) + return; + spin_lock_irq(q->queue_lock); if (!err) { q->rpm_status = RPM_ACTIVE; -- cgit v1.2.3 From 23688bf4f830a89866fd0ed3501e342a7360fe4f Mon Sep 17 00:00:00 2001 From: Junichi Nomura Date: Tue, 22 Dec 2015 10:23:44 -0700 Subject: block: ensure to split after potentially bouncing a bio blk_queue_bio() does split then bounce, which makes the segment counting based on pages before bouncing and could go wrong. Move the split to after bouncing, like we do for blk-mq, and the we fix the issue of having the bio count for segments be wrong. Fixes: 54efd50bfd87 ("block: make generic_make_request handle arbitrarily sized bios") Cc: stable@vger.kernel.org Tested-by: Artem S. Tashkinov Signed-off-by: Jens Axboe --- block/blk-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 3636be469fa2..c487b94c59e3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1689,8 +1689,6 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) struct request *req; unsigned int request_count = 0; - blk_queue_split(q, &bio, q->bio_split); - /* * low level driver can indicate that it wants pages above a * certain limit bounced to low memory (ie for highmem, or even @@ -1698,6 +1696,8 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) */ blk_queue_bounce(q, &bio); + blk_queue_split(q, &bio, q->bio_split); + if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { bio->bi_error = -EIO; bio_endio(bio); -- cgit v1.2.3