Commit 6cb72bc1 authored by Bart Van Assche's avatar Bart Van Assche Committed by Doug Ledford

IB/srp: Avoid that duplicate responses trigger a kernel bug

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: default avatarBart 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>
Cc: <stable@vger.kernel.org>
Reviewed-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent d6c58dc4
...@@ -1892,9 +1892,11 @@ static void srp_process_rsp(struct srp_rdma_ch *ch, struct srp_rsp *rsp) ...@@ -1892,9 +1892,11 @@ static void srp_process_rsp(struct srp_rdma_ch *ch, struct srp_rsp *rsp)
complete(&ch->tsk_mgmt_done); complete(&ch->tsk_mgmt_done);
} else { } else {
scmnd = scsi_host_find_tag(target->scsi_host, rsp->tag); scmnd = scsi_host_find_tag(target->scsi_host, rsp->tag);
if (scmnd) { if (scmnd && scmnd->host_scribble) {
req = (void *)scmnd->host_scribble; req = (void *)scmnd->host_scribble;
scmnd = srp_claim_req(ch, req, NULL, scmnd); scmnd = srp_claim_req(ch, req, NULL, scmnd);
} else {
scmnd = NULL;
} }
if (!scmnd) { if (!scmnd) {
shost_printk(KERN_ERR, target->scsi_host, shost_printk(KERN_ERR, target->scsi_host,
......
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