5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vaibhav Nagare <redacted>
commit 06aa3d26327f24edd039ff249672fdf6f2ba5695 upstream.
Under memory pressure, the qede driver encounters NULL pointer
dereferences when processing TPA continuation fragments.
Commit 8a8633978b84 ("qede: Add build_skb() support.") accidentally
dropped the assignment of tpa_info->buffer.data in qede_tpa_start().
When memory pressure causes an SKB allocation failure in qede_tpa_start(),
the driver sets tpa_start_fail = true and attempts to recycle the physical
page later in qede_tpa_end() via qede_reuse_page(). However, because
buffer.data was left uninitialized (NULL), qede_reuse_page() pushes a
"ghost" BD (valid DMA mapping but NULL data pointer) back into the
active Rx ring.
The next time the hardware uses this ring slot, it passes a NULL page
to qede_fill_frag_skb(), causing a kernel panic.
Example crash from production system:
BUG: unable to handle kernel NULL pointer dereference at 0x8
RIP: qede_fill_frag_skb+0x96/0x430 [qede]
Call Trace:
qede_rx_int+0xb06/0x1de0
qede_poll+0x2f4/0x6c0
__napi_poll+0x2d/0x130
Fix the root cause by restoring the tpa_info->buffer.data assignment
in qede_tpa_start(), ensuring valid pages are correctly tracked and
recycled. Additionally, update the stale comment for
struct qede_agg_info::buffer to reflect its current usage.
Fixes: 8a8633978b84 ("qede: Add build_skb() support.")
Cc: <redacted>
Signed-off-by: Vaibhav Nagare <redacted>
Link: https://patch.msgid.link/20260818073309.2266072-1-vnagare@redhat.com (local)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/qlogic/qede/qede.h | 8 ++++----
drivers/net/ethernet/qlogic/qede/qede_fp.c | 1 +
2 files changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/net/ethernet/qlogic/qede/qede.h
+++ b/drivers/net/ethernet/qlogic/qede/qede.h
@@ -305,10 +305,10 @@ enum qede_agg_state {
};
struct qede_agg_info {
- /* rx_buf is a data buffer that can be placed / consumed from rx bd
- * chain. It has two purposes: We will preallocate the data buffer
- * for each aggregation when we open the interface and will place this
- * buffer on the rx-bd-ring when we receive TPA_START. We don't want
+ /* buffer is used to retain the Rx consumer descriptor when a TPA
+ * session starts. If the SKB allocation fails during TPA_START,
+ * we use this saved buffer to safely recycle the physical page
+ * back into the rx-bd-ring via qede_reuse_page(). We don't want
* to be in a state where allocation fails, as we can't reuse the
* consumer buffer in the rx-chain since FW may still be writing to it
* (since header needs to be modified for TPA).
--- a/drivers/net/ethernet/qlogic/qede/qede_fp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c@@ -851,6 +851,7 @@ static void qede_tpa_start(struct qede_d
pad, false);
tpa_info->buffer.page_offset = sw_rx_data_cons->page_offset;
tpa_info->buffer.mapping = sw_rx_data_cons->mapping;
+ tpa_info->buffer.data = sw_rx_data_cons->data;
if (unlikely(!tpa_info->skb)) {
DP_NOTICE(edev, "Failed to allocate SKB for gro\n");