ccing Maurizio because he was working on the same issue. On 08/22/2018 12:37 PM, Laura Abbott wrote: > Fedora got a bug report of a crash with iSCSI: > > kernel BUG at include/linux/scatterlist.h:143! > ... > RIP: 0010:iscsit_do_crypto_hash_buf+0x154/0x180 [iscsi_target_mod] > ... > Call Trace: > ? iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod] > iscsit_get_rx_pdu+0x4cd/0xa90 [iscsi_target_mod] > ? native_sched_clock+0x3e/0xa0 > ? iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod] > iscsi_target_rx_thread+0x81/0xf0 [iscsi_target_mod] > kthread+0x120/0x140 > ? kthread_create_worker_on_cpu+0x70/0x70 > ret_from_fork+0x3a/0x50 > > This is a BUG_ON for using a stack buffer with a scatterlist. > There are two cases that trigger this bug. Switch to using a > dynamically allocated buffer for one case and do not assign > a NULL buffer in another case. > > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1615258 > Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx> > --- > drivers/target/iscsi/iscsi_target.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c > index 8e223799347a..8b40f0e99e2c 100644 > --- a/drivers/target/iscsi/iscsi_target.c > +++ b/drivers/target/iscsi/iscsi_target.c > @@ -1419,7 +1419,8 @@ static void iscsit_do_crypto_hash_buf(struct ahash_request *hash, > > sg_init_table(sg, ARRAY_SIZE(sg)); > sg_set_buf(sg, buf, payload_length); > - sg_set_buf(sg + 1, pad_bytes, padding); > + if (padding) > + sg_set_buf(sg + 1, pad_bytes, padding); > > ahash_request_set_crypt(hash, sg, data_crc, payload_length + padding); > > @@ -3913,10 +3914,14 @@ static bool iscsi_target_check_conn_state(struct iscsi_conn *conn) > static void iscsit_get_rx_pdu(struct iscsi_conn *conn) > { > int ret; > - u8 buffer[ISCSI_HDR_LEN], opcode; > + u8 *buffer, opcode; > u32 checksum = 0, digest = 0; > struct kvec iov; > > + buffer = kmalloc_array(ISCSI_HDR_LEN, sizeof(*buffer), GFP_KERNEL); > + if (!buffer) > + return; > + > while (!kthread_should_stop()) { > /* > * Ensure that both TX and RX per connection kthreads > @@ -3985,6 +3990,8 @@ static void iscsit_get_rx_pdu(struct iscsi_conn *conn) > if (ret < 0) > return; > } You need to also change all the returns to breaks between the kmalloc above and kfree here. > + kfree(buffer); > } > > int iscsi_target_rx_thread(void *arg) >
