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

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@kernel.org