From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D78B01917DE; Sun, 24 Nov 2024 12:39:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732451973; cv=none; b=cRdKKi6pQRb2AzQWqo0Y87a62FlZk5w96DFlUyEMX9wE69DTqUs5JuT6EHk7VQZ4k3jojAJ4QHC0D63ztycSZer+tYWtbAedrfpKmTDicrAtWm0XAoQvuvZd0w4UVmgLhng40IUq7rrl36wa/yO5iIqrWl2Fhxtwe/GBrWJeibw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732451973; c=relaxed/simple; bh=Wai5QgjNn6fP2jjYouXyrNsDJerhSLIVUPEOBCvjao8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NGIJC9z1+ket/p2tmOsOsOhOhYM77XkenMARGTDS1DMepdfCrPCwbgSjM1ZJq0VuGHlqKreSwzIDyA7N+6pME0HISUabW81NypVfWCf+8Nw8keMIxMBhnxR83cEGP+UE3CVlxiaamgBcvSXrdkvH1/xVeqVO0Cuma34x4ALBJxI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dj5nWtG1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dj5nWtG1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70DEAC4CED6; Sun, 24 Nov 2024 12:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732451973; bh=Wai5QgjNn6fP2jjYouXyrNsDJerhSLIVUPEOBCvjao8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dj5nWtG1CYDckKsKfyMzJuQTSUvwF3I5vaolXohsrshltX5frmFyUYYzhaIvIIz6b ZTIAGB8su0dyPfjy3K85/l719wdHhxewDsf3gpWIBiCEE5NAQW9dCJWO3zK+L0CYHN st+ewLirTC/m9h2SwMcuBgTI8nH3nXFsx1kxsaZZo72J2WiaFzRTCO6XC4+42AwwlU eCwQ1HeSk1M+4keCmJkbaKodY0LS201obvyd6VyoqOSbYZHSpZnHhWDzRz3zqIbtXf YZTLoIE+I1OzuE7IBpoOn8Qis0LuyxMyRAwcs/fi+dVrjPnlwoVadtSf6woEf23y6k sIVkGjn62uJ3Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johannes Thumshirn , Filipe Manana , David Sterba , Sasha Levin , clm@fb.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org Subject: [PATCH AUTOSEL 6.12 08/19] btrfs: don't take dev_replace rwsem on task already holding it Date: Sun, 24 Nov 2024 07:38:43 -0500 Message-ID: <20241124123912.3335344-8-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241124123912.3335344-1-sashal@kernel.org> References: <20241124123912.3335344-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.12.1 Content-Transfer-Encoding: 8bit From: Johannes Thumshirn [ Upstream commit 8cca35cb29f81eba3e96ec44dad8696c8a2f9138 ] Running fstests btrfs/011 with MKFS_OPTIONS="-O rst" to force the usage of the RAID stripe-tree, we get the following splat from lockdep: BTRFS info (device sdd): dev_replace from /dev/sdd (devid 1) to /dev/sdb started ============================================ WARNING: possible recursive locking detected 6.11.0-rc3-btrfs-for-next #599 Not tainted -------------------------------------------- btrfs/2326 is trying to acquire lock: ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250 but task is already holding lock: ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&fs_info->dev_replace.rwsem); lock(&fs_info->dev_replace.rwsem); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by btrfs/2326: #0: ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250 stack backtrace: CPU: 1 UID: 0 PID: 2326 Comm: btrfs Not tainted 6.11.0-rc3-btrfs-for-next #599 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack_lvl+0x5b/0x80 __lock_acquire+0x2798/0x69d0 ? __pfx___lock_acquire+0x10/0x10 ? __pfx___lock_acquire+0x10/0x10 lock_acquire+0x19d/0x4a0 ? btrfs_map_block+0x39f/0x2250 ? __pfx_lock_acquire+0x10/0x10 ? find_held_lock+0x2d/0x110 ? lock_is_held_type+0x8f/0x100 down_read+0x8e/0x440 ? btrfs_map_block+0x39f/0x2250 ? __pfx_down_read+0x10/0x10 ? do_raw_read_unlock+0x44/0x70 ? _raw_read_unlock+0x23/0x40 btrfs_map_block+0x39f/0x2250 ? btrfs_dev_replace_by_ioctl+0xd69/0x1d00 ? btrfs_bio_counter_inc_blocked+0xd9/0x2e0 ? __kasan_slab_alloc+0x6e/0x70 ? __pfx_btrfs_map_block+0x10/0x10 ? __pfx_btrfs_bio_counter_inc_blocked+0x10/0x10 ? kmem_cache_alloc_noprof+0x1f2/0x300 ? mempool_alloc_noprof+0xed/0x2b0 btrfs_submit_chunk+0x28d/0x17e0 ? __pfx_btrfs_submit_chunk+0x10/0x10 ? bvec_alloc+0xd7/0x1b0 ? bio_add_folio+0x171/0x270 ? __pfx_bio_add_folio+0x10/0x10 ? __kasan_check_read+0x20/0x20 btrfs_submit_bio+0x37/0x80 read_extent_buffer_pages+0x3df/0x6c0 btrfs_read_extent_buffer+0x13e/0x5f0 read_tree_block+0x81/0xe0 read_block_for_search+0x4bd/0x7a0 ? __pfx_read_block_for_search+0x10/0x10 btrfs_search_slot+0x78d/0x2720 ? __pfx_btrfs_search_slot+0x10/0x10 ? lock_is_held_type+0x8f/0x100 ? kasan_save_track+0x14/0x30 ? __kasan_slab_alloc+0x6e/0x70 ? kmem_cache_alloc_noprof+0x1f2/0x300 btrfs_get_raid_extent_offset+0x181/0x820 ? __pfx_lock_acquire+0x10/0x10 ? __pfx_btrfs_get_raid_extent_offset+0x10/0x10 ? down_read+0x194/0x440 ? __pfx_down_read+0x10/0x10 ? do_raw_read_unlock+0x44/0x70 ? _raw_read_unlock+0x23/0x40 btrfs_map_block+0x5b5/0x2250 ? __pfx_btrfs_map_block+0x10/0x10 scrub_submit_initial_read+0x8fe/0x11b0 ? __pfx_scrub_submit_initial_read+0x10/0x10 submit_initial_group_read+0x161/0x3a0 ? lock_release+0x20e/0x710 ? __pfx_submit_initial_group_read+0x10/0x10 ? __pfx_lock_release+0x10/0x10 scrub_simple_mirror.isra.0+0x3eb/0x580 scrub_stripe+0xe4d/0x1440 ? lock_release+0x20e/0x710 ? __pfx_scrub_stripe+0x10/0x10 ? __pfx_lock_release+0x10/0x10 ? do_raw_read_unlock+0x44/0x70 ? _raw_read_unlock+0x23/0x40 scrub_chunk+0x257/0x4a0 scrub_enumerate_chunks+0x64c/0xf70 ? __mutex_unlock_slowpath+0x147/0x5f0 ? __pfx_scrub_enumerate_chunks+0x10/0x10 ? bit_wait_timeout+0xb0/0x170 ? __up_read+0x189/0x700 ? scrub_workers_get+0x231/0x300 ? up_write+0x490/0x4f0 btrfs_scrub_dev+0x52e/0xcd0 ? create_pending_snapshots+0x230/0x250 ? __pfx_btrfs_scrub_dev+0x10/0x10 btrfs_dev_replace_by_ioctl+0xd69/0x1d00 ? lock_acquire+0x19d/0x4a0 ? __pfx_btrfs_dev_replace_by_ioctl+0x10/0x10 ? lock_release+0x20e/0x710 ? btrfs_ioctl+0xa09/0x74f0 ? __pfx_lock_release+0x10/0x10 ? do_raw_spin_lock+0x11e/0x240 ? __pfx_do_raw_spin_lock+0x10/0x10 btrfs_ioctl+0xa14/0x74f0 ? lock_acquire+0x19d/0x4a0 ? find_held_lock+0x2d/0x110 ? __pfx_btrfs_ioctl+0x10/0x10 ? lock_release+0x20e/0x710 ? do_sigaction+0x3f0/0x860 ? __pfx_do_vfs_ioctl+0x10/0x10 ? do_raw_spin_lock+0x11e/0x240 ? lockdep_hardirqs_on_prepare+0x270/0x3e0 ? _raw_spin_unlock_irq+0x28/0x50 ? do_sigaction+0x3f0/0x860 ? __pfx_do_sigaction+0x10/0x10 ? __x64_sys_rt_sigaction+0x18e/0x1e0 ? __pfx___x64_sys_rt_sigaction+0x10/0x10 ? __x64_sys_close+0x7c/0xd0 __x64_sys_ioctl+0x137/0x190 do_syscall_64+0x71/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f0bd1114f9b Code: Unable to access opcode bytes at 0x7f0bd1114f71. RSP: 002b:00007ffc8a8c3130 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f0bd1114f9b RDX: 00007ffc8a8c35e0 RSI: 00000000ca289435 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007 R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffc8a8c6c85 R13: 00000000398e72a0 R14: 0000000000004361 R15: 0000000000000004 This happens because on RAID stripe-tree filesystems we recurse back into btrfs_map_block() on scrub to perform the logical to device physical mapping. But as the device replace task is already holding the dev_replace::rwsem we deadlock. So don't take the dev_replace::rwsem in case our task is the task performing the device replace. Suggested-by: Filipe Manana Signed-off-by: Johannes Thumshirn Reviewed-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/dev-replace.c | 2 ++ fs/btrfs/fs.h | 2 ++ fs/btrfs/volumes.c | 8 +++++--- 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 83d5cdd77f293..604399e59a3d1 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -641,6 +641,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, return ret; down_write(&dev_replace->rwsem); + dev_replace->replace_task = current; switch (dev_replace->replace_state) { case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: @@ -994,6 +995,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list); fs_devices->rw_devices++; + dev_replace->replace_task = NULL; up_write(&dev_replace->rwsem); btrfs_rm_dev_replace_blocked(fs_info); diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h index 79f64e383eddf..cbfb225858a59 100644 --- a/fs/btrfs/fs.h +++ b/fs/btrfs/fs.h @@ -317,6 +317,8 @@ struct btrfs_dev_replace { struct percpu_counter bio_counter; wait_queue_head_t replace_wait; + + struct task_struct *replace_task; }; /* diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index eb51b609190fb..920df7585b0d1 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6481,13 +6481,15 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, max_len = btrfs_max_io_len(map, map_offset, &io_geom); *length = min_t(u64, map->chunk_len - map_offset, max_len); - down_read(&dev_replace->rwsem); + if (dev_replace->replace_task != current) + down_read(&dev_replace->rwsem); + dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace); /* * Hold the semaphore for read during the whole operation, write is * requested at commit time but must wait. */ - if (!dev_replace_is_ongoing) + if (!dev_replace_is_ongoing && dev_replace->replace_task != current) up_read(&dev_replace->rwsem); switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) { @@ -6627,7 +6629,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, bioc->mirror_num = io_geom.mirror_num; out: - if (dev_replace_is_ongoing) { + if (dev_replace_is_ongoing && dev_replace->replace_task != current) { lockdep_assert_held(&dev_replace->rwsem); /* Unlock and let waiting writers proceed */ up_read(&dev_replace->rwsem); -- 2.43.0