在 2024/01/18 2:22, Mikulas Patocka 写道:
RCU protection was removed in the commit 2d32777d60de ("raid1: remove rcu
protection to access rdev from conf").
However, the code in fix_read_error does rcu_dereference outside
rcu_read_lock - this triggers the following warning. The warning is
triggered by a LVM2 test shell/integrity-caching.sh.
This commit removes rcu_dereference.
=============================
WARNING: suspicious RCU usage
6.7.0 #2 Not tainted
-----------------------------
drivers/md/raid1.c:2265 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
no locks held by mdX_raid1/1859.
stack backtrace:
CPU: 2 PID: 1859 Comm: mdX_raid1 Not tainted 6.7.0 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x60/0x70
lockdep_rcu_suspicious+0x153/0x1b0
raid1d+0x1732/0x1750 [raid1]
? lock_acquire+0x9f/0x270
? finish_wait+0x3d/0x80
? md_thread+0xf7/0x130 [md_mod]
? lock_release+0xaa/0x230
? md_register_thread+0xd0/0xd0 [md_mod]
md_thread+0xa0/0x130 [md_mod]
? housekeeping_test_cpu+0x30/0x30
kthread+0xdc/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x28/0x40
? kthread_complete_and_exit+0x20/0x20
ret_from_fork_asm+0x11/0x20
</TASK>
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Fixes: ca294b34aaf3 ("md/raid1: support read error check")
LGTM
Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/raid1.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/drivers/md/raid1.c
===================================================================
--- linux-2.6.orig/drivers/md/raid1.c
+++ linux-2.6/drivers/md/raid1.c
@@ -2262,7 +2262,7 @@ static void fix_read_error(struct r1conf
int sectors = r1_bio->sectors;
int read_disk = r1_bio->read_disk;
struct mddev *mddev = conf->mddev;
- struct md_rdev *rdev = rcu_dereference(conf->mirrors[read_disk].rdev);
+ struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
if (exceed_read_errors(mddev, rdev)) {
r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
.
