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AJvYcCX6Qjawx7jIRLrCTd/qqp2BfPDT5Pax8Kmej8YNB0ezYxMtlvaK55Kx1Y6PONG5ijpoOxuN6PSBqnfEIcvd@vger.kernel.org X-Gm-Message-State: AOJu0YwAmqTXjFooZEX67Suz7i+ZpHSvEtQrWss7C35x8MJr5gbujOdo uLJqAgoSIgtJx0YMOjy4LQSDaONuJBUojToEbAVyZzZLvGq0Ext1i+T0uRf9bEoDcOz1YdFNAf1 ebgfuqWOIHjkf9LIBw4ibW9mNOsfR4hLYlx83aZcBjxWgO4CxzvbyNzE= X-Google-Smtp-Source: AGHT+IEI8Fm+ngcAScAw3GZ+NipnXHnpue0z2vk2s83Py6BMfT1btpH7zPlB8xEQn7qHc0VWjeGLNUVysHgH6ZPN7Sw0Fi41YoLy Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a92:c56a:0:b0:3a7:dfe4:bd33 with SMTP id e9e14a558f8ab-3a7fecc82b3mr58583675ab.6.1733323143026; Wed, 04 Dec 2024 06:39:03 -0800 (PST) Date: Wed, 04 Dec 2024 06:39:03 -0800 In-Reply-To: <1129891.1733321485@warthog.procyon.org.uk> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <67506987.050a0220.17bd51.006f.GAE@google.com> Subject: Re: [syzbot] [netfs?] kernel BUG in iov_iter_revert (2) From: syzbot To: dhowells@redhat.com, jlayton@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netfs@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: possible deadlock in __submit_bio ====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc1-syzkaller-dirty #0 Not tainted ------------------------------------------------------ kswapd0/75 is trying to acquire lock: ffff888034c41438 (&q->q_usage_counter(io)#37){++++}-{0:0}, at: __submit_bio+0x2c6/0x560 block/blk-core.c:629 but task is already holding lock: ffffffff8ea35b00 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6864 [inline] ffffffff8ea35b00 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x36f0 mm/vmscan.c:7246 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __fs_reclaim_acquire mm/page_alloc.c:3851 [inline] fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3865 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4055 [inline] slab_alloc_node mm/slub.c:4133 [inline] __do_kmalloc_node mm/slub.c:4282 [inline] __kmalloc_node_noprof+0xb2/0x4d0 mm/slub.c:4289 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:650 sbitmap_init_node+0x2d4/0x670 lib/sbitmap.c:132 scsi_realloc_sdev_budget_map+0x2a7/0x460 drivers/scsi/scsi_scan.c:246 scsi_add_lun drivers/scsi/scsi_scan.c:1106 [inline] scsi_probe_and_add_lun+0x3173/0x4bd0 drivers/scsi/scsi_scan.c:1287 __scsi_add_device+0x228/0x2f0 drivers/scsi/scsi_scan.c:1622 ata_scsi_scan_host+0x236/0x740 drivers/ata/libata-scsi.c:4575 async_run_entry_fn+0xa8/0x420 kernel/async.c:129 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (&q->q_usage_counter(io)#37){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1536/0x2390 block/blk-mq.c:3091 __submit_bio+0x2c6/0x560 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739 swap_writepage_bdev_async mm/page_io.c:451 [inline] __swap_writepage+0x5fc/0x1400 mm/page_io.c:474 swap_writepage+0x8f4/0x1170 mm/page_io.c:289 pageout mm/vmscan.c:689 [inline] shrink_folio_list+0x3c0e/0x8cb0 mm/vmscan.c:1367 evict_folios+0x5568/0x7be0 mm/vmscan.c:4593 try_to_shrink_lruvec+0x9a6/0xc70 mm/vmscan.c:4789 shrink_one+0x3b9/0x850 mm/vmscan.c:4834 shrink_many mm/vmscan.c:4897 [inline] lru_gen_shrink_node mm/vmscan.c:4975 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5956 kswapd_shrink_node mm/vmscan.c:6785 [inline] balance_pgdat mm/vmscan.c:6977 [inline] kswapd+0x1ca9/0x36f0 mm/vmscan.c:7246 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&q->q_usage_counter(io)#37); lock(fs_reclaim); rlock(&q->q_usage_counter(io)#37); *** DEADLOCK *** 1 lock held by kswapd0/75: #0: ffffffff8ea35b00 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6864 [inline] #0: ffffffff8ea35b00 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x36f0 mm/vmscan.c:7246 stack backtrace: CPU: 0 UID: 0 PID: 75 Comm: kswapd0 Not tainted 6.13.0-rc1-syzkaller-dirty #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1536/0x2390 block/blk-mq.c:3091 __submit_bio+0x2c6/0x560 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739 swap_writepage_bdev_async mm/page_io.c:451 [inline] __swap_writepage+0x5fc/0x1400 mm/page_io.c:474 swap_writepage+0x8f4/0x1170 mm/page_io.c:289 pageout mm/vmscan.c:689 [inline] shrink_folio_list+0x3c0e/0x8cb0 mm/vmscan.c:1367 evict_folios+0x5568/0x7be0 mm/vmscan.c:4593 try_to_shrink_lruvec+0x9a6/0xc70 mm/vmscan.c:4789 shrink_one+0x3b9/0x850 mm/vmscan.c:4834 shrink_many mm/vmscan.c:4897 [inline] lru_gen_shrink_node mm/vmscan.c:4975 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5956 kswapd_shrink_node mm/vmscan.c:6785 [inline] balance_pgdat mm/vmscan.c:6977 [inline] kswapd+0x1ca9/0x36f0 mm/vmscan.c:7246 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Tested on: commit: 40384c84 Linux 6.13-rc1 git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.13-rc1 console output: https://syzkaller.appspot.com/x/log.txt?x=101560f8580000 kernel config: https://syzkaller.appspot.com/x/.config?x=58639d2215ba9a07 dashboard link: https://syzkaller.appspot.com/bug?extid=404b4b745080b6210c6c compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 patch: https://syzkaller.appspot.com/x/patch.diff?x=138c4de8580000