From f4fa3424c66255ba1e07b26becfc3d6cab0fdf65 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 26 May 2011 21:01:38 +0200 Subject: [PATCH] block: fix oops on !disk->queue and sysfs discard alignment display Eric Dumazet reports: ---- At boot, I have a crash in part_discard_alignment_show+0x1b/0x50 CR2 : 000006ac fault in : mov 0x2c(%rcx),%edx I suspect commit 23ceb5b7719e9276d4 (block: Remove extra discard_alignment from hd_struct) being in fault ---- Not quite known how ->queue can be NULL while the sysfs entry exists, but lets play it safe and check for a NULL queue. The rest of the sysfs show strategies in check.c do not dereference disk->queue. Reported-by: Eric Dumazet Signed-off-by: Jens Axboe --- fs/partitions/check.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/partitions/check.c b/fs/partitions/check.c index 8ed4d3433199..f82e762eeca2 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -256,10 +256,12 @@ ssize_t part_discard_alignment_show(struct device *dev, { struct hd_struct *p = dev_to_part(dev); struct gendisk *disk = dev_to_disk(dev); + unsigned int alignment = 0; - return sprintf(buf, "%u\n", - queue_limit_discard_alignment(&disk->queue->limits, - p->start_sect)); + if (disk->queue) + alignment = queue_limit_discard_alignment(&disk->queue->limits, + p->start_sect); + return sprintf(buf, "%u\n", alignment); } ssize_t part_stat_show(struct device *dev, -- 2.20.1