This is a note to let you know that I've just added the patch titled
md: Replace snprintf with scnprintf
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-replace-snprintf-with-scnprintf.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 523ba87cb0a82486c3db217581501415d68c549a
Author: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
Date: Tue Aug 23 11:51:04 2022 -0700
md: Replace snprintf with scnprintf
[ Upstream commit 1727fd5015d8f93474148f94e34cda5aa6ad4a43 ]
Current code produces a warning as shown below when total characters
in the constituent block device names plus the slashes exceeds 200.
snprintf() returns the number of characters generated from the given
input, which could cause the expression “200 – len” to wrap around
to a large positive number. Fix this by using scnprintf() instead,
which returns the actual number of characters written into the buffer.
[ 1513.267938] ------------[ cut here ]------------
[ 1513.267943] WARNING: CPU: 15 PID: 37247 at <snip>/lib/vsprintf.c:2509 vsnprintf+0x2c8/0x510
[ 1513.267944] Modules linked in: <snip>
[ 1513.267969] CPU: 15 PID: 37247 Comm: mdadm Not tainted 5.4.0-1085-azure #90~18.04.1-Ubuntu
[ 1513.267969] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 05/09/2022
[ 1513.267971] RIP: 0010:vsnprintf+0x2c8/0x510
<-snip->
[ 1513.267982] Call Trace:
[ 1513.267986] snprintf+0x45/0x70
[ 1513.267990] ? disk_name+0x71/0xa0
[ 1513.267993] dump_zones+0x114/0x240 [raid0]
[ 1513.267996] ? _cond_resched+0x19/0x40
[ 1513.267998] raid0_run+0x19e/0x270 [raid0]
[ 1513.268000] md_run+0x5e0/0xc50
[ 1513.268003] ? security_capable+0x3f/0x60
[ 1513.268005] do_md_run+0x19/0x110
[ 1513.268006] md_ioctl+0x195e/0x1f90
[ 1513.268007] blkdev_ioctl+0x91f/0x9f0
[ 1513.268010] block_ioctl+0x3d/0x50
[ 1513.268012] do_vfs_ioctl+0xa9/0x640
[ 1513.268014] ? __fput+0x162/0x260
[ 1513.268016] ksys_ioctl+0x75/0x80
[ 1513.268017] __x64_sys_ioctl+0x1a/0x20
[ 1513.268019] do_syscall_64+0x5e/0x200
[ 1513.268021] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: 766038846e875 ("md/raid0: replace printk() with pr_*()")
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Acked-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 4a80cf43304b..823ea5cca774 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -47,7 +47,7 @@ static void dump_zones(struct mddev *mddev)
int len = 0;
for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
- len += snprintf(line+len, 200-len, "%s%pg", k?"/":"",
+ len += scnprintf(line+len, 200-len, "%s%pg", k?"/":"",
conf->devlist[j * raid_disks + k]->bdev);
pr_debug("md: zone%d=[%s]\n", j, line);
