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Subject[PATCH] scsi: sd: skip checks when media is present if sd_read_capacity reports zero
Date
In sd_revalidate_disk, if sdkp->media_present is set, then sdkp->capacity
should not be zero. Therefore, jump to end of if block and skip remaining
checks/calls. Fixes a KMSAN-found uninit-value bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=197c8a3a2de61720a9b500ad485a7aba0065c6af

Reported-by: syzbot+6b02c1da3865f750164a@syzkaller.appspotmail.com
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
---
drivers/scsi/sd.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index ed0b1bb99f08..a7fe53f492ae 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3201,6 +3201,8 @@ static int sd_revalidate_disk(struct gendisk *disk)
*/
if (sdkp->media_present) {
sd_read_capacity(sdkp, buffer);
+ if (!sdkp->capacity)
+ goto present_block_end;

/*
* set the default to rotational. All non-rotational devices
@@ -3226,6 +3228,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
sd_read_write_same(sdkp, buffer);
sd_read_security(sdkp, buffer);
}
+present_block_end:

/*
* We now have all cache related info, determine how we deal
--
2.30.2
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