* FAILED: patch "[PATCH] scsi: core: Fill in DMA padding bytes in" failed to apply to 6.1-stable tree
@ 2026-09-03 14:17 gregkh
2026-09-07 9:02 ` [PATCH 6.1.y] scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables() Petr Vaganov
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2026-09-03 14:17 UTC (permalink / raw)
To: p.vaganov, bvanassche, mkp; +Cc: stable
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 626147717bea776b61ed3631d2c26283760c4cc4
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090346-overboard-amplify-cbc7@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 626147717bea776b61ed3631d2c26283760c4cc4 Mon Sep 17 00:00:00 2001
From: Petr Vaganov <p.vaganov@ideco.ru>
Date: Mon, 29 Jun 2026 01:52:21 +0700
Subject: [PATCH] scsi: core: Fill in DMA padding bytes in
scsi_alloc_sgtables()
During fuzz testing, the following issue was discovered:
BUG: KMSAN: uninit-value in __dma_map_sg_attrs+0x217/0x310
__dma_map_sg_attrs+0x217/0x310
dma_map_sg_attrs+0x4a/0x70
ata_qc_issue+0x9f8/0x1420
__ata_scsi_queuecmd+0x1657/0x1740
ata_scsi_queuecmd+0x79a/0x920
scsi_queue_rq+0x4472/0x4f40
blk_mq_dispatch_rq_list+0x1cca/0x3ee0
__blk_mq_sched_dispatch_requests+0x458/0x630
blk_mq_sched_dispatch_requests+0x15b/0x340
__blk_mq_run_hw_queue+0xe5/0x250
__blk_mq_delay_run_hw_queue+0x138/0x780
blk_mq_run_hw_queue+0x4bb/0x7e0
blk_mq_sched_insert_request+0x2a7/0x4c0
blk_execute_rq+0x497/0x8a0
sg_io+0xbe0/0xe20
scsi_ioctl+0x2b36/0x3c60
sr_block_ioctl+0x319/0x440
blkdev_ioctl+0x80f/0xd70
__se_sys_ioctl+0x219/0x420
__x64_sys_ioctl+0x93/0xe0
x64_sys_call+0x1d6c/0x3ad0
do_syscall_64+0x4c/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Uninit was created at:
__alloc_pages+0x5c0/0xc80
alloc_pages+0xe0e/0x1050
blk_rq_map_user_iov+0x2b77/0x6100
blk_rq_map_user_io+0x2fa/0x4d0
sg_io+0xad6/0xe20
scsi_ioctl+0x2b36/0x3c60
sr_block_ioctl+0x319/0x440
blkdev_ioctl+0x80f/0xd70
__se_sys_ioctl+0x219/0x420
__x64_sys_ioctl+0x93/0xe0
x64_sys_call+0x1d6c/0x3ad0
do_syscall_64+0x4c/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Bytes 14-15 of 16 are uninitialized
Memory access of size 16 starts at ffff88800cbdb000
When processing the last unaligned element of the scatterlist, it is
supplemented with missing bytes in the amount of pad_len. These bytes
remain uninitialized, which leads to a problem.
Extend last_sg->length by pad_len first, then use sg_zero_buffer() to
zero those pad_len bytes. sg_zero_buffer() uses sg_miter internally,
which correctly handles sg entries spanning multiple pages and padding
that crosses a page boundary.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 40b01b9bbdf5 ("block: update bio according to DMA alignment padding")
Cc: stable@vger.kernel.org
Signed-off-by: Petr Vaganov <p.vaganov@ideco.ru>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260628185229.37957-1-p.vaganov@ideco.ru
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 22e2e3223440..686cef2406b3 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1187,8 +1187,10 @@ blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
if (blk_rq_bytes(rq) & rq->q->limits.dma_pad_mask) {
unsigned int pad_len =
(rq->q->limits.dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
+ unsigned int data_len = last_sg->length;
last_sg->length += pad_len;
+ sg_zero_buffer(last_sg, 1, pad_len, data_len);
cmd->extra_len += pad_len;
}
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 6.1.y] scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables()
2026-09-03 14:17 FAILED: patch "[PATCH] scsi: core: Fill in DMA padding bytes in" failed to apply to 6.1-stable tree gregkh
@ 2026-09-07 9:02 ` Petr Vaganov
0 siblings, 0 replies; 2+ messages in thread
From: Petr Vaganov @ 2026-09-07 9:02 UTC (permalink / raw)
To: stable; +Cc: Petr Vaganov, Bart Van Assche, Martin K. Petersen (Oracle)
From: Petr Vaganov <p.vaganov@ideco.ru>
During fuzz testing, the following issue was discovered:
BUG: KMSAN: uninit-value in __dma_map_sg_attrs+0x217/0x310
__dma_map_sg_attrs+0x217/0x310
dma_map_sg_attrs+0x4a/0x70
ata_qc_issue+0x9f8/0x1420
__ata_scsi_queuecmd+0x1657/0x1740
ata_scsi_queuecmd+0x79a/0x920
scsi_queue_rq+0x4472/0x4f40
blk_mq_dispatch_rq_list+0x1cca/0x3ee0
__blk_mq_sched_dispatch_requests+0x458/0x630
blk_mq_sched_dispatch_requests+0x15b/0x340
__blk_mq_run_hw_queue+0xe5/0x250
__blk_mq_delay_run_hw_queue+0x138/0x780
blk_mq_run_hw_queue+0x4bb/0x7e0
blk_mq_sched_insert_request+0x2a7/0x4c0
blk_execute_rq+0x497/0x8a0
sg_io+0xbe0/0xe20
scsi_ioctl+0x2b36/0x3c60
sr_block_ioctl+0x319/0x440
blkdev_ioctl+0x80f/0xd70
__se_sys_ioctl+0x219/0x420
__x64_sys_ioctl+0x93/0xe0
x64_sys_call+0x1d6c/0x3ad0
do_syscall_64+0x4c/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Uninit was created at:
__alloc_pages+0x5c0/0xc80
alloc_pages+0xe0e/0x1050
blk_rq_map_user_iov+0x2b77/0x6100
blk_rq_map_user_io+0x2fa/0x4d0
sg_io+0xad6/0xe20
scsi_ioctl+0x2b36/0x3c60
sr_block_ioctl+0x319/0x440
blkdev_ioctl+0x80f/0xd70
__se_sys_ioctl+0x219/0x420
__x64_sys_ioctl+0x93/0xe0
x64_sys_call+0x1d6c/0x3ad0
do_syscall_64+0x4c/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Bytes 14-15 of 16 are uninitialized
Memory access of size 16 starts at ffff88800cbdb000
When processing the last unaligned element of the scatterlist, it is
supplemented with missing bytes in the amount of pad_len. These bytes
remain uninitialized, which leads to a problem.
Extend last_sg->length by pad_len first, then use sg_zero_buffer() to
zero those pad_len bytes. sg_zero_buffer() uses sg_miter internally,
which correctly handles sg entries spanning multiple pages and padding
that crosses a page boundary.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 40b01b9bbdf5 ("block: update bio according to DMA alignment padding")
Cc: stable@vger.kernel.org
Signed-off-by: Petr Vaganov <p.vaganov@ideco.ru>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260628185229.37957-1-p.vaganov@ideco.ru
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>
(cherry picked from commit 626147717bea776b61ed3631d2c26283760c4cc4)
Signed-off-by: Petr Vaganov <p.vaganov@ideco.ru>
---
drivers/scsi/scsi_lib.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index ddc986ff5161..5c56e942758e 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1070,8 +1070,10 @@ blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
unsigned int pad_len =
(rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
+ unsigned int data_len = last_sg->length;
last_sg->length += pad_len;
+ sg_zero_buffer(last_sg, 1, pad_len, data_len);
cmd->extra_len += pad_len;
}
--
2.55.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-07 9:03 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
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2026-09-03 14:17 FAILED: patch "[PATCH] scsi: core: Fill in DMA padding bytes in" failed to apply to 6.1-stable tree gregkh
2026-09-07 9:02 ` [PATCH 6.1.y] scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables() Petr Vaganov
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