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 <[email protected]>
---
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;
}
+
+ kfree(buffer);
}
int iscsi_target_rx_thread(void *arg)
--
2.17.1
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 <[email protected]>
> ---
> 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)
>