5.4-stable review patch. If anyone has any objections, please let me know.
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From: Showrya M N showrya@chelsio.com
[ Upstream commit 3ea3a256ed81f95ab0f3281a0e234b01a9cae605 ]
In case of an ib_fast_reg_mr allocation failure during iSER setup, the machine hits a panic because iscsi_conn->dd_data is initialized unconditionally, even when no memory is allocated (dd_size == 0). This leads invalid pointer dereference during connection teardown.
Fix by setting iscsi_conn->dd_data only if memory is actually allocated.
Panic trace: ------------ iser: iser_create_fastreg_desc: Failed to allocate ib_fast_reg_mr err=-12 iser: iser_alloc_rx_descriptors: failed allocating rx descriptors / data buffers BUG: unable to handle page fault for address: fffffffffffffff8 RIP: 0010:swake_up_locked.part.5+0xa/0x40 Call Trace: complete+0x31/0x40 iscsi_iser_conn_stop+0x88/0xb0 [ib_iser] iscsi_stop_conn+0x66/0xc0 [scsi_transport_iscsi] iscsi_if_stop_conn+0x14a/0x150 [scsi_transport_iscsi] iscsi_if_rx+0x1135/0x1834 [scsi_transport_iscsi] ? netlink_lookup+0x12f/0x1b0 ? netlink_deliver_tap+0x2c/0x200 netlink_unicast+0x1ab/0x280 netlink_sendmsg+0x257/0x4f0 ? _copy_from_user+0x29/0x60 sock_sendmsg+0x5f/0x70
Signed-off-by: Showrya M N showrya@chelsio.com Signed-off-by: Potnuri Bharat Teja bharat@chelsio.com Link: https://lore.kernel.org/r/20250627112329.19763-1-showrya@chelsio.com Reviewed-by: Chris Leech cleech@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/libiscsi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index f3cee64c6d12..9b94218ff04c 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2893,7 +2893,8 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size, conn = cls_conn->dd_data; memset(conn, 0, sizeof(*conn) + dd_size);
- conn->dd_data = cls_conn->dd_data + sizeof(*conn); + if (dd_size) + conn->dd_data = cls_conn->dd_data + sizeof(*conn); conn->session = session; conn->cls_conn = cls_conn; conn->c_stage = ISCSI_CONN_INITIAL_STAGE;