6.12-stable review patch. If anyone has any objections, please let me know.
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From: Liu Jian liujian56@huawei.com
[ Upstream commit ba1e9421cf1a8369d25c3832439702a015d6b5f9 ]
BUG: kernel NULL pointer dereference, address: 00000000000002ec PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G OE 6.17.0-rc2+ #9 NONE Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 Workqueue: smc_hs_wq smc_listen_work [smc] RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc] ... Call Trace: <TASK> smcr_buf_map_link+0x211/0x2a0 [smc] __smc_buf_create+0x522/0x970 [smc] smc_buf_create+0x3a/0x110 [smc] smc_find_rdma_v2_device_serv+0x18f/0x240 [smc] ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc] smc_listen_find_device+0x1dd/0x2b0 [smc] smc_listen_work+0x30f/0x580 [smc] process_one_work+0x18c/0x340 worker_thread+0x242/0x360 kthread+0xe7/0x220 ret_from_fork+0x13a/0x160 ret_from_fork_asm+0x1a/0x30 </TASK>
If the software RoCE device is used, ibdev->dma_device is a null pointer. As a result, the problem occurs. Null pointer detection is added to prevent problems.
Fixes: 0ef69e788411c ("net/smc: optimize for smc_sndbuf_sync_sg_for_device and smc_rmb_sync_sg_for_cpu") Signed-off-by: Liu Jian liujian56@huawei.com Reviewed-by: Guangguan Wang guangguan.wang@linux.alibaba.com Reviewed-by: Zhu Yanjun yanjun.zhu@linux.dev Reviewed-by: D. Wythe alibuda@linux.alibaba.com Link: https://patch.msgid.link/20250828124117.2622624-1-liujian56@huawei.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/smc_ib.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c index 9c563cdbea908..fc07fc4ed9986 100644 --- a/net/smc/smc_ib.c +++ b/net/smc/smc_ib.c @@ -743,6 +743,9 @@ bool smc_ib_is_sg_need_sync(struct smc_link *lnk, unsigned int i; bool ret = false;
+ if (!lnk->smcibdev->ibdev->dma_device) + return ret; + /* for now there is just one DMA address */ for_each_sg(buf_slot->sgt[lnk->link_idx].sgl, sg, buf_slot->sgt[lnk->link_idx].nents, i) {