linux-kernel - [PATCH][v3] afs: Remove erroneous seq |= 1 in volume lookup loop

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20250910084235.2630-1-lirongqing@baidu.com>
Date: Wed, 10 Sep 2025 16:42:35 +0800
From: lirongqing <roy.qing.li@...il.com>
To: dhowells@...hat.com,
	marc.dionne@...istor.com,
	linux-afs@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	oleg@...hat.com
Cc: Li RongQing <lirongqing@...du.com>
Subject: [PATCH][v3] afs: Remove erroneous seq |= 1 in volume lookup loop

From: Li RongQing <lirongqing@...du.com>

The `seq |= 1` operation in the volume lookup loop is incorrect because:
seq is already incremented at start, making it odd in next iteration
which triggers lock, but The `|= 1` operation causes seq to be even
and unintended lockless operation

Remove this erroneous operation to maintain proper lock sequencing.

Fixes: 32222f09782f ("afs: Apply server breaks to mmap'd files in the call processor")
Reviewed-by: Oleg Nesterov <oleg@...hat.com>
Signed-off-by: Li RongQing <lirongqing@...du.com>
---
Diff with v2: add Reviewed-by, and Fixes tag
Diff with v1: rewrite the changelog

 fs/afs/callback.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/afs/callback.c b/fs/afs/callback.c
index 69e1dd5..2c0d274 100644
--- a/fs/afs/callback.c
+++ b/fs/afs/callback.c
@@ -140,7 +140,6 @@ static struct afs_volume *afs_lookup_volume_rcu(struct afs_cell *cell,
 			break;
 		if (!need_seqretry(&cell->volume_lock, seq))
 			break;
-		seq |= 1; /* Want a lock next time */
 	}
 
 	done_seqretry(&cell->volume_lock, seq);
-- 
2.9.4