Re: [PATCH v3] zram: don't free statically defined names

Sergey Senozhatsky
2024-09-24T05:17:49Z

On (24/09/24 10:42), Sergey Senozhatsky wrote:
> On (24/09/23 19:48), Andrey Skvortsov wrote:
> > When CONFIG_ZRAM_MULTI_COMP isn't set ZRAM_SECONDARY_COMP can hold
> > default_compressor, because it's the same offset as ZRAM_PRIMARY_COMP,
> > so we need to make sure that we don't attempt to kfree() the
> > statically defined compressor name.
> >
> > This is detected by KASAN.
> >
> > ==================================================================
> > Call trace:
> > kfree+0x60/0x3a0
> > zram_destroy_comps+0x98/0x198 [zram]
> > zram_reset_device+0x22c/0x4a8 [zram]
> > reset_store+0x1bc/0x2d8 [zram]
> > dev_attr_store+0x44/0x80
> > sysfs_kf_write+0xfc/0x188
> > kernfs_fop_write_iter+0x28c/0x428
> > vfs_write+0x4dc/0x9b8
> > ksys_write+0x100/0x1f8
> > __arm64_sys_write+0x74/0xb8
> > invoke_syscall+0xd8/0x260
> > el0_svc_common.constprop.0+0xb4/0x240
> > do_el0_svc+0x48/0x68
> > el0_svc+0x40/0xc8
> > el0t_64_sync_handler+0x120/0x130
> > el0t_64_sync+0x190/0x198
> > ==================================================================
> >
> > Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
> > Fixes: 684826f8271a ("zram: free secondary algorithms names")
> > Cc: <stable@vger.kernel.org>
>
> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>

As a minor side note, I'd still prefer to drop that backtrace from
the commit message - we know that reset_store() is called from sysfs
write, there is nothing new (nor important) in that call trace.