Re: [PATCH v2] mpt3sas: Avoid test/set_bit() operating in non-allocated memory

[Keith Busch]

On Wed, Jun 05, 2024 at 01:55:29AM -0700, Breno Leitao wrote:
> There is a potential out-of-bounds access when using test_bit() on a
> single word. The test_bit() and set_bit() functions operate on long
> values, and when testing or setting a single word, they can exceed the
> word boundary. KASAN detects this issue and produces a dump:
> 
> 	 BUG: KASAN: slab-out-of-bounds in _scsih_add_device.constprop.0 (./arch/x86/include/asm/bitops.h:60 ./include/asm-generic/bitops/instrumented-atomic.h:29 drivers/scsi/mpt3sas/mpt3sas_scsih.c:7331) mpt3sas
> 
> 	 Write of size 8 at addr ffff8881d26e3c60 by task kworker/u1536:2/2965
> 
> For full log, please look at [1].
> 
> Make the allocation at least the size of sizeof(unsigned long) so that
> set_bit() and test_bit() have sufficient room for read/write operations
> without overwriting unallocated memory.

Looks good.

Reviewed-by: Keith Busch <kbusch@xxxxxxxxxx>