This is a note to let you know that I've just added the patch titled IB/srp: Avoid that duplicate responses trigger a kernel bug to the 4.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ib-srp-avoid-that-duplicate-responses-trigger-a-kernel-bug.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 6cb72bc1b40bb2c1750ee7a5ebade93bed49a5fb Mon Sep 17 00:00:00 2001 From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Date: Tue, 14 Feb 2017 10:56:30 -0800 Subject: IB/srp: Avoid that duplicate responses trigger a kernel bug From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> commit 6cb72bc1b40bb2c1750ee7a5ebade93bed49a5fb upstream. After srp_process_rsp() returns there is a short time during which the scsi_host_find_tag() call will return a pointer to the SCSI command that is being completed. If during that time a duplicate response is received, avoid that the following call stack appears: BUG: unable to handle kernel NULL pointer dereference at (null) IP: srp_recv_done+0x450/0x6b0 [ib_srp] Oops: 0000 [#1] SMP CPU: 10 PID: 0 Comm: swapper/10 Not tainted 4.10.0-rc7-dbg+ #1 Call Trace: <IRQ> __ib_process_cq+0x4b/0xd0 [ib_core] ib_poll_handler+0x1d/0x70 [ib_core] irq_poll_softirq+0xba/0x120 __do_softirq+0xba/0x4c0 irq_exit+0xbe/0xd0 smp_apic_timer_interrupt+0x38/0x50 apic_timer_interrupt+0x90/0xa0 </IRQ> RIP: srp_recv_done+0x450/0x6b0 [ib_srp] RSP: ffff88046f483e20 Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Cc: Israel Rukshin <israelr@xxxxxxxxxxxx> Cc: Max Gurtovoy <maxg@xxxxxxxxxxxx> Cc: Laurence Oberman <loberman@xxxxxxxxxx> Cc: Steve Feeley <Steve.Feeley@xxxxxxxxxxx> Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/infiniband/ulp/srp/ib_srp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -1892,9 +1892,11 @@ static void srp_process_rsp(struct srp_r complete(&ch->tsk_mgmt_done); } else { scmnd = scsi_host_find_tag(target->scsi_host, rsp->tag); - if (scmnd) { + if (scmnd && scmnd->host_scribble) { req = (void *)scmnd->host_scribble; scmnd = srp_claim_req(ch, req, NULL, scmnd); + } else { + scmnd = NULL; } if (!scmnd) { shost_printk(KERN_ERR, target->scsi_host, Patches currently in stable-queue which might be from bart.vanassche@xxxxxxxxxxx are queue-4.10/ib-srp-avoid-that-duplicate-responses-trigger-a-kernel-bug.patch queue-4.10/ib-srp-fix-race-conditions-related-to-task-management.patch queue-4.10/ib-srp-avoid-using-ib_mr_type_sg_gaps.patch