CVE-2024-35852

In the Linux kernel, the following vulnerability has been resolved: mlxsw:
spectrum_acl_tcam: Fix memory leak when canceling rehash work The rehash
delayed work is rescheduled with a delay if the number of credits at end of
the work is not negative as supposedly it means that the migration ended.
Otherwise, it is rescheduled immediately. After “mlxsw: spectrum_acl_tcam:
Fix possible use-after-free during rehash” the above is no longer accurate
as a non-negative number of credits is no longer indicative of the
migration being done. It can also happen if the work encountered an error
in which case the migration will resume the next time the work is
scheduled. The significance of the above is that it is possible for the
work to be pending and associated with hints that were allocated when the
migration started. This leads to the hints being leaked [1] when the work
is canceled while pending as part of ACL region dismantle. Fix by freeing
the hints if hints are associated with a work that was canceled while
pending. Blame the original commit since the reliance on not having a
pending work associated with hints is fragile. [1] unreferenced object
0xffff88810e7c3000 (size 256): comm “kworker/0:16”, pid 176, jiffies
4295460353 hex dump (first 32 bytes): 00 30 95 11 81 88 ff ff 61 00 00 00
00 00 00 80 .0…a… 00 00 61 00 40 00 00 00 00 00 00 00 04 00 00
00 …a.@… backtrace (crc 2544ddb9): [<00000000cf8cfab3>]
kmalloc_trace+0x23f/0x2a0 [<000000004d9a1ad9>] objagg_hints_get+0x42/0x390
[<000000000b143cf3>] mlxsw_sp_acl_erp_rehash_hints_get+0xca/0x400
[<0000000059bdb60a>] mlxsw_sp_acl_tcam_vregion_rehash_work+0x868/0x1160
[<00000000e81fd734>] process_one_work+0x59c/0xf20 [<00000000ceee9e81>]
worker_thread+0x799/0x12c0 [<00000000bda6fe39>] kthread+0x246/0x300
[<0000000070056d23>] ret_from_fork+0x34/0x70 [<00000000dea2b93e>]
ret_from_fork_asm+0x1a/0x30