Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 22/63] IB/srp: Avoid that duplicate responses trigger a kernel bug | Date | Mon, 13 Mar 2017 16:39:09 +0800 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Bart Van Assche <bart.vanassche@sandisk.com>
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@sandisk.com> Cc: Israel Rukshin <israelr@mellanox.com> Cc: Max Gurtovoy <maxg@mellanox.com> Cc: Laurence Oberman <loberman@redhat.com> Cc: Steve Feeley <Steve.Feeley@sandisk.com> Reviewed-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 @@ -1880,9 +1880,11 @@ 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,
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