Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: fw_tracer, return NULL on create error

Tracer creation can fail by returning either NULL or ERR_PTR. The return value is stored without a check on the device, and users treat ERR_PTR and NULL the same way. This also causes a crash in the core dump logic, which is missing the ERR_PTR check and ends up dereferencing it, as shown in the trace below.

Switch tracer creation to return NULL on failure only, so callers only need a single NULL check.

Internal error: Oops: 0000000096000006 [#1] SMP Modules linked in: mlx5_ib ib_uverbs ib_core ipv6 mlx5_core CPU: 1 UID: 0 PID: 12 Comm: kworker/u16:0 Not tainted 6.19.7 #1 PREEMPT(none) Workqueue: mlx5_health0001:01:00.0 mlx5_fw_reporter_err_work [mlx5_core] pstate: a3400009 (NzCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : mlx5_fw_tracer_trigger_core_dump_general+0x58/0xe0 [mlx5_core] lr : mlx5_fw_tracer_trigger_core_dump_general+0x40/0xe0 [mlx5_core] sp : ffff800081cf3c40 x29: ffff800081cf3c90 x28: 0000000000000000 x27: 0000000000000000 x26: ffff000080018828 x25: 0000000000000000 x24: ffff000080304a05 x23: ffff800081cf3d80 x22: ffff0000847e01a0 x21: 0000000000000000 x20: ffff0000847e01a0 x19: ffffffffffffffa1 x18: ffff80008310bbf0 x17: ffff800080119650 x16: ffff80008010df54 x15: ffff80008010d4ac x14: ffff800079c202e4 x13: ffff80008002fe60 x12: ffff800080119650 x11: ffff80008010df54 x10: ffff80008010d4ac x9 : ffff800079c203…