FAILED: patch "[PATCH] qed: fix double free in qed_cxt_tables_alloc()" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 2bccfb8476ca5f3548afbd623dc7a6980d4e77de
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026052808-multitask-shelf-9b39@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2bccfb8476ca5f3548afbd623dc7a6980d4e77de Mon Sep 17 00:00:00 2001
From: Dawei Feng <dawei.feng@seu.edu.cn>
Date: Wed, 20 May 2026 15:03:23 +0800
Subject: [PATCH] qed: fix double free in qed_cxt_tables_alloc()

If one of the later PF or VF CID bitmap allocations fails,
qed_cid_map_alloc() jumps to cid_map_fail and frees the previously
allocated CID bitmaps before returning an error. qed_cxt_tables_alloc()
then calls qed_cxt_mngr_free(), which invokes qed_cid_map_free()
again.

Fix this by setting each CID bitmap pointer to NULL after bitmap_free()
to avoid double free.

The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1-rc3.

Runtime reproduction was not attempted because exercising the failing
allocation path requires device-specific setup.

Fixes: fe56b9e6a8d9 ("qed: Add module with basic common support")
Cc: stable@vger.kernel.org
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
Link: https://patch.msgid.link/20260520070323.2762379-1-dawei.feng@seu.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/qlogic/qed/qed_cxt.c b/drivers/net/ethernet/qlogic/qed/qed_cxt.c
index 9861daa82d9e..b70262e70baf 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_cxt.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_cxt.c
@@ -1036,11 +1036,13 @@ static void qed_cid_map_free(struct qed_hwfn *p_hwfn)
 
 	for (type = 0; type < MAX_CONN_TYPES; type++) {
 		bitmap_free(p_mngr->acquired[type].cid_map);
+		p_mngr->acquired[type].cid_map = NULL;
 		p_mngr->acquired[type].max_count = 0;
 		p_mngr->acquired[type].start_cid = 0;
 
 		for (vf = 0; vf < MAX_NUM_VFS; vf++) {
 			bitmap_free(p_mngr->acquired_vf[type][vf].cid_map);
+			p_mngr->acquired_vf[type][vf].cid_map = NULL;
 			p_mngr->acquired_vf[type][vf].max_count = 0;
 			p_mngr->acquired_vf[type][vf].start_cid = 0;
 		}