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authorCheng Xu <chengyou@linux.alibaba.com>2022-04-24 16:01:03 +0800
committerJason Gunthorpe <jgg@nvidia.com>2022-05-04 20:59:54 -0300
commitef91271c65c12d36e4c2b61c61d4849fb6d11aa0 (patch)
tree2995445a2fffbfb79041d7329724d094c2e2ef95 /drivers/infiniband
parent1c9043ae0667a43bd87beeebbdd4bed674713629 (diff)
downloadlinux-ef91271c65c12d36e4c2b61c61d4849fb6d11aa0.tar.gz
RDMA/siw: Fix a condition race issue in MPA request processing
The calling of siw_cm_upcall and detaching new_cep with its listen_cep
should be atomistic semantics. Otherwise siw_reject may be called in a
temporary state, e,g, siw_cm_upcall is called but the new_cep->listen_cep
has not being cleared.

This fixes a WARN:

  WARNING: CPU: 7 PID: 201 at drivers/infiniband/sw/siw/siw_cm.c:255 siw_cep_put+0x125/0x130 [siw]
  CPU: 2 PID: 201 Comm: kworker/u16:22 Kdump: loaded Tainted: G            E     5.17.0-rc7 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
  Workqueue: iw_cm_wq cm_work_handler [iw_cm]
  RIP: 0010:siw_cep_put+0x125/0x130 [siw]
  Call Trace:
   <TASK>
   siw_reject+0xac/0x180 [siw]
   iw_cm_reject+0x68/0xc0 [iw_cm]
   cm_work_handler+0x59d/0xe20 [iw_cm]
   process_one_work+0x1e2/0x3b0
   worker_thread+0x50/0x3a0
   ? rescuer_thread+0x390/0x390
   kthread+0xe5/0x110
   ? kthread_complete_and_exit+0x20/0x20
   ret_from_fork+0x1f/0x30
   </TASK>

Fixes: 6c52fdc244b5 ("rdma/siw: connection management")
Link: https://lore.kernel.org/r/d528d83466c44687f3872eadcb8c184528b2e2d4.1650526554.git.chengyou@linux.alibaba.com
Reported-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Cheng Xu <chengyou@linux.alibaba.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/sw/siw/siw_cm.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
index 7acdd3c3a599..17f34d584cd9 100644
--- a/drivers/infiniband/sw/siw/siw_cm.c
+++ b/drivers/infiniband/sw/siw/siw_cm.c
@@ -968,14 +968,15 @@ static void siw_accept_newconn(struct siw_cep *cep)
 
 		siw_cep_set_inuse(new_cep);
 		rv = siw_proc_mpareq(new_cep);
-		siw_cep_set_free(new_cep);
-
 		if (rv != -EAGAIN) {
 			siw_cep_put(cep);
 			new_cep->listen_cep = NULL;
-			if (rv)
+			if (rv) {
+				siw_cep_set_free(new_cep);
 				goto error;
+			}
 		}
+		siw_cep_set_free(new_cep);
 	}
 	return;