The patch below does not apply to the 4.14-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.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e151db8ecfb019b7da31d076130a794574c89f6f Mon Sep 17 00:00:00 2001 From: Mikulas Patocka mpatocka@redhat.com Date: Sun, 24 Jul 2022 14:26:12 -0400 Subject: [PATCH] md-raid: destroy the bitmap after destroying the thread
When we ran the lvm test "shell/integrity-blocksize-3.sh" on a kernel with kasan, we got failure in write_page.
The reason for the failure is that md_bitmap_destroy is called before destroying the thread and the thread may be waiting in the function write_page for the bio to complete. When the thread finishes waiting, it executes "if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))", which triggers the kasan warning.
Note that the commit 48df498daf62 that caused this bug claims that it is neede for md-cluster, you should check md-cluster and possibly find another bugfix for it.
BUG: KASAN: use-after-free in write_page+0x18d/0x680 [md_mod] Read of size 8 at addr ffff889162030c78 by task mdX_raid1/5539
CPU: 10 PID: 5539 Comm: mdX_raid1 Not tainted 5.19.0-rc2 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report.cold+0x45/0x57a ? __lock_text_start+0x18/0x18 ? write_page+0x18d/0x680 [md_mod] kasan_report+0xa8/0xe0 ? write_page+0x18d/0x680 [md_mod] kasan_check_range+0x13f/0x180 write_page+0x18d/0x680 [md_mod] ? super_sync+0x4d5/0x560 [dm_raid] ? md_bitmap_file_kick+0xa0/0xa0 [md_mod] ? rs_set_dev_and_array_sectors+0x2e0/0x2e0 [dm_raid] ? mutex_trylock+0x120/0x120 ? preempt_count_add+0x6b/0xc0 ? preempt_count_sub+0xf/0xc0 md_update_sb+0x707/0xe40 [md_mod] md_reap_sync_thread+0x1b2/0x4a0 [md_mod] md_check_recovery+0x533/0x960 [md_mod] raid1d+0xc8/0x2a20 [raid1] ? var_wake_function+0xe0/0xe0 ? psi_group_change+0x411/0x500 ? preempt_count_sub+0xf/0xc0 ? _raw_spin_lock_irqsave+0x78/0xc0 ? __lock_text_start+0x18/0x18 ? raid1_end_read_request+0x2a0/0x2a0 [raid1] ? preempt_count_sub+0xf/0xc0 ? _raw_spin_unlock_irqrestore+0x19/0x40 ? del_timer_sync+0xa9/0x100 ? try_to_del_timer_sync+0xc0/0xc0 ? _raw_spin_lock_irqsave+0x78/0xc0 ? __lock_text_start+0x18/0x18 ? __list_del_entry_valid+0x68/0xa0 ? finish_wait+0xa3/0x100 md_thread+0x161/0x260 [md_mod] ? unregister_md_personality+0xa0/0xa0 [md_mod] ? _raw_spin_lock_irqsave+0x78/0xc0 ? prepare_to_wait_event+0x2c0/0x2c0 ? unregister_md_personality+0xa0/0xa0 [md_mod] kthread+0x148/0x180 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 </TASK>
Allocated by task 5522: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x80/0xa0 md_bitmap_create+0xa8/0xe80 [md_mod] md_run+0x777/0x1300 [md_mod] raid_ctr+0x249c/0x4a30 [dm_raid] dm_table_add_target+0x2b0/0x620 [dm_mod] table_load+0x1c8/0x400 [dm_mod] ctl_ioctl+0x29e/0x560 [dm_mod] dm_compat_ctl_ioctl+0x7/0x20 [dm_mod] __do_compat_sys_ioctl+0xfa/0x160 do_syscall_64+0x90/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Freed by task 5680: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x40 kasan_set_free_info+0x20/0x40 __kasan_slab_free+0xf7/0x140 kfree+0x80/0x240 md_bitmap_free+0x1c3/0x280 [md_mod] __md_stop+0x21/0x120 [md_mod] md_stop+0x9/0x40 [md_mod] raid_dtr+0x1b/0x40 [dm_raid] dm_table_destroy+0x98/0x1e0 [dm_mod] __dm_destroy+0x199/0x360 [dm_mod] dev_remove+0x10c/0x160 [dm_mod] ctl_ioctl+0x29e/0x560 [dm_mod] dm_compat_ctl_ioctl+0x7/0x20 [dm_mod] __do_compat_sys_ioctl+0xfa/0x160 do_syscall_64+0x90/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Cc: stable@vger.kernel.org Fixes: 48df498daf62 ("md: move bitmap_destroy to the beginning of __md_stop") Signed-off-by: Song Liu song@kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk
diff --git a/drivers/md/md.c b/drivers/md/md.c index 6e82df21623d..35b895813c88 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -6238,11 +6238,11 @@ static void mddev_detach(struct mddev *mddev) static void __md_stop(struct mddev *mddev) { struct md_personality *pers = mddev->pers; - md_bitmap_destroy(mddev); mddev_detach(mddev); /* Ensure ->event_work is done */ if (mddev->event_work.func) flush_workqueue(md_misc_wq); + md_bitmap_destroy(mddev); spin_lock(&mddev->lock); mddev->pers = NULL; spin_unlock(&mddev->lock);