* Re: [PATCH] sysfs: upgrade OOB write by buggy .show hook into WARNing
[not found] ` <3cc3e8c6-c6e8-4625-a88f-f5708b935dab@p183>
@ 2026-05-07 9:28 ` Danilo Krummrich
2026-05-07 13:52 ` Alexey Dobriyan
0 siblings, 1 reply; 2+ messages in thread
From: Danilo Krummrich @ 2026-05-07 9:28 UTC (permalink / raw)
To: Alexey Dobriyan
Cc: Greg Kroah-Hartman, Rafael J. Wysocki, linux-fsdevel, driver-core
(Cc: driver-core)
On Thu May 7, 2026 at 11:01 AM CEST, Alexey Dobriyan wrote:
> Buggy .show hook will get just 1 line of dmesg:
>
> fill_read_buffer: ext4_attr_show+0x0/0x600 returned bad count
>
> It may or may not oops later in some unrelated process.
>
> But buggy .show hook most likely is corrupting random memory past sysfs
> buffer therefore deserving more. WARN, make it more visible and let
> QA machines panic earlier.
>
> Also, delete useless cast -- "count" is >=0 at this point.
>
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
NIT: This patch also cleans up the stale "fill_read_buffer:" prefix, and instead
points out the actual caller, which could be mentioned in the commit message --
no need to resend for this though.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] sysfs: upgrade OOB write by buggy .show hook into WARNing
2026-05-07 9:28 ` [PATCH] sysfs: upgrade OOB write by buggy .show hook into WARNing Danilo Krummrich
@ 2026-05-07 13:52 ` Alexey Dobriyan
0 siblings, 0 replies; 2+ messages in thread
From: Alexey Dobriyan @ 2026-05-07 13:52 UTC (permalink / raw)
To: Danilo Krummrich
Cc: Greg Kroah-Hartman, Rafael J. Wysocki, linux-fsdevel, driver-core
On Thu, May 07, 2026 at 11:28:29AM +0200, Danilo Krummrich wrote:
> (Cc: driver-core)
>
> On Thu May 7, 2026 at 11:01 AM CEST, Alexey Dobriyan wrote:
> > Buggy .show hook will get just 1 line of dmesg:
> >
> > fill_read_buffer: ext4_attr_show+0x0/0x600 returned bad count
> >
> > It may or may not oops later in some unrelated process.
> >
> > But buggy .show hook most likely is corrupting random memory past sysfs
> > buffer therefore deserving more. WARN, make it more visible and let
> > QA machines panic earlier.
> >
> > Also, delete useless cast -- "count" is >=0 at this point.
> >
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
>
> NIT: This patch also cleans up the stale "fill_read_buffer:" prefix, and instead
> points out the actual caller, which could be mentioned in the commit message --
> no need to resend for this though.
Yes. WARN prints enough information to locate the bug, so stale function
name just goes away.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-05-07 9:28 ` [PATCH] sysfs: upgrade OOB write by buggy .show hook into WARNing Danilo Krummrich
2026-05-07 13:52 ` Alexey Dobriyan
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