Re: [PATCH rdma] RDMA/bnxt_re: cmds completions handler avoid accessing invalid memeory

[Leon Romanovsky <leon@kernel.org>]

On Tue, Nov 12, 2024 at 03:49:56PM +0200, Mohammad Heib wrote:
> If bnxt FW behaves unexpectedly because of FW bug or unexpected behavior it
> can send completions for old  cookies that have already been handled by the
> bnxt driver. If that old cookie was associated with an old calling context
> the driver will try to access that caller memory again because the driver
> never clean the is_waiter_alive flag after the caller successfully complete
> waiting, and this access will cause the following kernel panic:
> 
> Call Trace:
>  <IRQ>
>  ? __die+0x20/0x70
>  ? page_fault_oops+0x75/0x170
>  ? exc_page_fault+0xaa/0x140
>  ? asm_exc_page_fault+0x22/0x30
>  ? bnxt_qplib_process_qp_event.isra.0+0x20c/0x3a0 [bnxt_re]
>  ? srso_return_thunk+0x5/0x5f
>  ? __wake_up_common+0x78/0xa0
>  ? srso_return_thunk+0x5/0x5f
>  bnxt_qplib_service_creq+0x18d/0x250 [bnxt_re]
>  tasklet_action_common+0xac/0x210
>  handle_softirqs+0xd3/0x2b0
>  __irq_exit_rcu+0x9b/0xc0
>  common_interrupt+0x7f/0xa0
>  </IRQ>
>  <TASK>
> 
> To avoid the above unexpected behavior clear the is_waiter_alive flag
> every time the caller finishes waiting for a completion.
> 
> Fixes: 691eb7c6110f ("RDMA/bnxt_re: handle command completions after driver detect a timedout")
> Signed-off-by: Mohammad Heib <mheib@redhat.com>
> ---
>  drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)

Selvin?