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* [PATCH] md : Replace snprintf with scnprintf
@ 2022-08-04 17:25 Saurabh Sengar
  2022-08-04 18:38 ` Michael Kelley (LINUX)
  2022-08-05  1:10 ` Guoqing Jiang
  0 siblings, 2 replies; 4+ messages in thread
From: Saurabh Sengar @ 2022-08-04 17:25 UTC (permalink / raw)
  To: song, shli, neilb, linux-raid, linux-kernel, ssengar, mikelley

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_*()")
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
---
 drivers/md/raid0.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index b21e101..b6f0fc1 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -48,7 +48,7 @@ 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%s", k?"/":"",
+			len += scnprintf(line+len, 200-len, "%s%s", k?"/":"",
 					bdevname(conf->devlist[j*raid_disks
 							       + k]->bdev, b));
 		pr_debug("md: zone%d=[%s]\n", j, line);
-- 
1.8.3.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* RE: [PATCH] md : Replace snprintf with scnprintf
  2022-08-04 17:25 [PATCH] md : Replace snprintf with scnprintf Saurabh Sengar
@ 2022-08-04 18:38 ` Michael Kelley (LINUX)
  2022-08-05  1:10 ` Guoqing Jiang
  1 sibling, 0 replies; 4+ messages in thread
From: Michael Kelley (LINUX) @ 2022-08-04 18:38 UTC (permalink / raw)
  To: Saurabh Sengar, song, shli, neilb, linux-raid, linux-kernel,
	Saurabh Singh Sengar

From: Saurabh Sengar <ssengar@linux.microsoft.com> Sent: Thursday, August 4, 2022 10:26 AM
> 
> 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_*()")
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
>  drivers/md/raid0.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index b21e101..b6f0fc1 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -48,7 +48,7 @@ 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%s", k?"/":"",
> +			len += scnprintf(line+len, 200-len, "%s%s", k?"/":"",
>  					bdevname(conf->devlist[j*raid_disks
>  							       + k]->bdev, b));
>  		pr_debug("md: zone%d=[%s]\n", j, line);
> --
> 1.8.3.1

Reviewed-by: Michael Kelley <mikelley@microsoft.com>


^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] md : Replace snprintf with scnprintf
  2022-08-04 17:25 [PATCH] md : Replace snprintf with scnprintf Saurabh Sengar
  2022-08-04 18:38 ` Michael Kelley (LINUX)
@ 2022-08-05  1:10 ` Guoqing Jiang
  2022-08-23 18:07   ` Song Liu
  1 sibling, 1 reply; 4+ messages in thread
From: Guoqing Jiang @ 2022-08-05  1:10 UTC (permalink / raw)
  To: Saurabh Sengar, song, shli, neilb, linux-raid, linux-kernel,
	ssengar, mikelley



On 8/5/22 1:25 AM, Saurabh Sengar wrote:
> 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_*()")
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> ---
>   drivers/md/raid0.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index b21e101..b6f0fc1 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -48,7 +48,7 @@ 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%s", k?"/":"",
> +			len += scnprintf(line+len, 200-len, "%s%s", k?"/":"",
>   					bdevname(conf->devlist[j*raid_disks
>   							       + k]->bdev, b));
>   		pr_debug("md: zone%d=[%s]\n", j, line);

Acked-by: Guoqing Jiang <guoqing.jiang@linux.dev>

Thanks,
Guoqing

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] md : Replace snprintf with scnprintf
  2022-08-05  1:10 ` Guoqing Jiang
@ 2022-08-23 18:07   ` Song Liu
  0 siblings, 0 replies; 4+ messages in thread
From: Song Liu @ 2022-08-23 18:07 UTC (permalink / raw)
  To: Guoqing Jiang
  Cc: Saurabh Sengar, Shaohua Li, NeilBrown, linux-raid, open list,
	ssengar, mikelley

On Thu, Aug 4, 2022 at 6:10 PM Guoqing Jiang <guoqing.jiang@linux.dev> wrote:
>
>
>
> On 8/5/22 1:25 AM, Saurabh Sengar wrote:
> > 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_*()")
> > Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>

The patch doesn't apply. Could you please rebase and resend?

Thanks,
Song

> > ---
> >   drivers/md/raid0.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> > index b21e101..b6f0fc1 100644
> > --- a/drivers/md/raid0.c
> > +++ b/drivers/md/raid0.c
> > @@ -48,7 +48,7 @@ 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%s", k?"/":"",
> > +                     len += scnprintf(line+len, 200-len, "%s%s", k?"/":"",
> >                                       bdevname(conf->devlist[j*raid_disks
> >                                                              + k]->bdev, b));
> >               pr_debug("md: zone%d=[%s]\n", j, line);
>
> Acked-by: Guoqing Jiang <guoqing.jiang@linux.dev>
>
> Thanks,
> Guoqing

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-08-23 19:24 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-04 17:25 [PATCH] md : Replace snprintf with scnprintf Saurabh Sengar
2022-08-04 18:38 ` Michael Kelley (LINUX)
2022-08-05  1:10 ` Guoqing Jiang
2022-08-23 18:07   ` Song Liu

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