From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f70.google.com (mail-oo1-f70.google.com [209.85.161.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C9423E958E for ; Thu, 26 Feb 2026 14:54:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772117670; cv=none; b=rQmIzXvZaBaO0DsWQWD+b3H1YCDYxvywiXo6078cPcnJoLodjjMi05lvoo4TQ590p3zzwUVGioerOE+QkcHBWeHt8CODZ0vdAIi5pkQ8zAO7DXUijbVUlCfNKaNhaVpFF8rY2Km2rqWswUYzU4QkIttGBGytu3Fwkfu1UmsKuDs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772117670; c=relaxed/simple; bh=OI+TdJuHRvKlRHJBH9sfXd8aMtr2nfpVqcTfMWdH8Yc=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=gOhyIJlZ2PPnYyLchAFUFbeeboI9k1wzvz3FN91GKAP+ApiqkpTKPnXs72k1UuGCZK6m4/YhTfv9w/Wss+mZbX996mHoXEEWK4H1hoBRnmxOhbEXjdgJLFXcIJH0WFw/cQzO96nJ2qlcdpX9LEfKGnkw/YEQRaYI7kA9l0HZ1ec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f70.google.com with SMTP id 006d021491bc7-679dc77d151so18550529eaf.0 for ; Thu, 26 Feb 2026 06:54:28 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772117667; x=1772722467; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=CjIxbpBO1scmAMZRw3qust2CYmZD1FB5uYSGVYcBLCQ=; b=YU3xBFrpFbi02Dd9caj/Fu0L9bdWEdYGdgjGZ8PGx1+q4uHeQMT2Mem2IfApVoZYq9 2eiEEgjL177Qqs3Gy/lyJ4juD8odnCpcc/v0jueJqf9X36BvVCyR0xCjMCgRIXyLC1sV 8ObZMDNjxTifkkqLmxqc+sv3UE/FT0xUNos3dd263PSHXaF4DagWNiUKj58EBRLHWd49 ptjoyNZfICeBOodp3VoRGdR8W986szMzC7ljc8qsef2LwZRh3DKxMTuc13N1K8i3X4+q y8Uqt6dZ8RPCdU9bQXAHMLqKm1++ySk/qTRFzbOdDSz/MZpVJEbEDqEKHDdFfW8XHj8h FP4g== X-Forwarded-Encrypted: i=1; AJvYcCUFtSeDF2x3AxiJ9j8ga204pMtZFQac2au4O+EQAH1LLvdveDiqXgoqNDsvIPhSqrnrLAf3oTnSh3GkOTo=@vger.kernel.org X-Gm-Message-State: AOJu0YwJx8ZBkp1R/OZ2c1bFkoWb8zcM60u1qb8b6+63CPvOilhvr+WR oK5OSE9g4ndGx8MCOSAkPa8ReqD9B5ho72JgMfDVOBI3HurIKUr12Hwg9P7CbRA6xPVpNL+nf5G KItATijpOMXZGs8bh3s6eMK5IhLOhsAuj1QeGuxRQgxMPRC5qUQ+C/6CFZRk= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2916:b0:662:f91f:4a85 with SMTP id 006d021491bc7-679f3da6b32mr1315227eaf.54.1772117667232; Thu, 26 Feb 2026 06:54:27 -0800 (PST) Date: Thu, 26 Feb 2026 06:54:27 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69a05ea3.050a0220.305b49.0022.GAE@google.com> Subject: [syzbot] [mm?] possible deadlock in lock_mm_and_find_vma (4) From: syzbot To: Liam.Howlett@oracle.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, shakeel.butt@linux.dev, surenb@google.com, syzkaller-bugs@googlegroups.com, vbabka@suse.cz Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 32a92f8c8932 Convert more 'alloc_obj' cases to default GFP.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13cd6f3a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6259cfbe2d15cac4 dashboard link: https://syzkaller.appspot.com/bug?extid=709f5ab0e03871dec50a compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/64d473c704b2/disk-32a92f8c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/570c8f79c450/vmlinux-32a92f8c.xz kernel image: https://storage.googleapis.com/syzbot-assets/b3d4ccd686ce/bzImage-32a92f8c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+709f5ab0e03871dec50a@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.3.3387/17804 is trying to acquire lock: ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline] ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages+0x166/0x5f0 mm/page_alloc.c:5018 but task is already holding lock: ffff88807ad4b440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline] ffff88807ad4b440 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline] ffff88807ad4b440 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x35/0x6f0 mm/mmap_lock.c:501 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xde/0x140 mm/memory.c:7217 _inline_copy_from_user include/linux/uaccess.h:169 [inline] _copy_from_user+0x29/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] copy_from_sockptr_offset include/linux/sockptr.h:48 [inline] copy_from_sockptr include/linux/sockptr.h:61 [inline] do_ip_setsockopt+0x2363/0x3200 net/ipv4/ip_sockglue.c:1294 ip_setsockopt+0x5a/0xf0 net/ipv4/ip_sockglue.c:1417 ipv6_setsockopt+0x155/0x170 net/ipv6/ipv6_sockglue.c:968 tcp_setsockopt+0xa7/0x100 net/ipv4/tcp.c:4217 smc_setsockopt+0x1b6/0xa10 net/smc/af_smc.c:3097 do_sock_setsockopt+0xf3/0x1d0 net/socket.c:2322 __sys_setsockopt+0x119/0x190 net/socket.c:2347 __do_sys_setsockopt net/socket.c:2353 [inline] __se_sys_setsockopt net/socket.c:2350 [inline] __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2350 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #6 (k-sk_lock-AF_INET6){+.+.}-{0:0}: lock_sock_nested+0x41/0xf0 net/core/sock.c:3780 lock_sock include/net/sock.h:1709 [inline] inet_shutdown+0x67/0x410 net/ipv4/af_inet.c:913 nbd_mark_nsock_dead+0xae/0x5c0 drivers/block/nbd.c:318 sock_shutdown+0x16b/0x200 drivers/block/nbd.c:411 nbd_clear_sock drivers/block/nbd.c:1427 [inline] nbd_config_put+0x1eb/0x750 drivers/block/nbd.c:1451 nbd_release+0xb7/0x190 drivers/block/nbd.c:1756 blkdev_put_whole+0xb0/0xf0 block/bdev.c:737 bdev_release+0x47f/0x6d0 block/bdev.c:1160 blkdev_release+0x15/0x20 block/fops.c:705 __fput+0x3ff/0xb40 fs/file_table.c:469 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #5 (&nsock->tx_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 nbd_handle_cmd drivers/block/nbd.c:1143 [inline] nbd_queue_rq+0x428/0x1080 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386 blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969 __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] __submit_bio+0x584/0x6c0 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x562/0xc10 block/blk-core.c:753 submit_bio_noacct+0xd17/0x2010 block/blk-core.c:884 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x59c/0x770 fs/buffer.c:2821 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2458 filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2496 do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4096 read_mapping_folio include/linux/pagemap.h:1028 [inline] read_part_sector+0xd1/0x370 block/partitions/core.c:723 adfspart_check_ICS+0x93/0x910 block/partitions/acorn.c:360 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7f8/0xc80 block/partitions/core.c:694 blkdev_get_whole+0x187/0x290 block/bdev.c:764 bdev_open+0x2c7/0xe40 block/bdev.c:973 blkdev_open+0x34e/0x4f0 block/fops.c:697 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (&cmd->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 nbd_queue_rq+0xba/0x1080 drivers/block/nbd.c:1199 blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x23c/0x670 block/blk-mq.c:2386 blk_mq_dispatch_list+0x51d/0x1360 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969 __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] __submit_bio+0x584/0x6c0 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x562/0xc10 block/blk-core.c:753 submit_bio_noacct+0xd17/0x2010 block/blk-core.c:884 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x59c/0x770 fs/buffer.c:2821 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x4c8/0x8e0 fs/buffer.c:2458 filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2496 do_read_cache_folio+0x2d7/0x6b0 mm/filemap.c:4096 read_mapping_folio include/linux/pagemap.h:1028 [inline] read_part_sector+0xd1/0x370 block/partitions/core.c:723 adfspart_check_ICS+0x93/0x910 block/partitions/acorn.c:360 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7f8/0xc80 block/partitions/core.c:694 blkdev_get_whole+0x187/0x290 block/bdev.c:764 bdev_open+0x2c7/0xe40 block/bdev.c:973 blkdev_open+0x34e/0x4f0 block/fops.c:697 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (set->srcu){.+.+}-{0:0}: srcu_lock_sync include/linux/srcu.h:199 [inline] __synchronize_srcu+0xa1/0x2a0 kernel/rcu/srcutree.c:1505 blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline] blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline] blk_mq_quiesce_queue block/blk-mq.c:304 [inline] blk_mq_quiesce_queue+0x149/0x1c0 block/blk-mq.c:299 elevator_switch+0x17b/0x7e0 block/elevator.c:576 elevator_change+0x352/0x530 block/elevator.c:681 elevator_set_default+0x29e/0x360 block/elevator.c:754 blk_register_queue+0x412/0x590 block/blk-sysfs.c:940 __add_disk+0x73f/0xe40 block/genhd.c:528 add_disk_fwnode+0x118/0x5c0 block/genhd.c:597 add_disk include/linux/blkdev.h:785 [inline] nbd_dev_add+0x77a/0xb10 drivers/block/nbd.c:1984 nbd_init+0x291/0x2b0 drivers/block/nbd.c:2692 do_one_initcall+0x11d/0x760 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692 kernel_init+0x1f/0x1e0 init/main.c:1582 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (&q->elevator_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 queue_requests_store+0x38b/0x660 block/blk-sysfs.c:117 queue_attr_store+0x25f/0x2f0 block/blk-sysfs.c:866 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_pwrite64 fs/read_write.c:795 [inline] __do_sys_pwrite64 fs/read_write.c:803 [inline] __se_sys_pwrite64 fs/read_write.c:800 [inline] __x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:800 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&q->q_usage_counter(io)#26){++++}-{0:0}: blk_alloc_queue+0x610/0x790 block/blk-core.c:461 blk_mq_alloc_queue+0x174/0x290 block/blk-mq.c:4429 __blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4476 loop_add+0x498/0xb60 drivers/block/loop.c:2049 loop_init+0x1d3/0x200 drivers/block/loop.c:2288 do_one_initcall+0x11d/0x760 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692 kernel_init+0x1f/0x1e0 init/main.c:1582 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] prepare_alloc_pages+0x166/0x5f0 mm/page_alloc.c:5018 __alloc_frozen_pages_noprof+0x19a/0x2ba0 mm/page_alloc.c:5239 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2484 alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2575 pagetable_alloc_noprof include/linux/mm.h:3404 [inline] pmd_alloc_one_noprof include/asm-generic/pgalloc.h:143 [inline] __pmd_alloc+0x3b/0x9c0 mm/memory.c:6709 pmd_alloc include/linux/mm.h:3320 [inline] __handle_mm_fault+0xa99/0x2b60 mm/memory.c:6406 handle_mm_fault+0x36d/0xa20 mm/memory.c:6623 do_user_addr_fault+0x74c/0x12f0 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:53 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] _inline_copy_from_user include/linux/uaccess.h:185 [inline] _copy_from_user+0x98/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] get_user_ifreq+0x77/0x1c0 net/socket.c:3350 br_ioctl_stub+0x23d/0x4d0 net/bridge/br_ioctl.c:409 br_ioctl_call+0x53/0xa0 net/socket.c:1227 sock_ioctl+0x616/0x6b0 net/socket.c:1329 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: fs_reclaim --> k-sk_lock-AF_INET6 --> &mm->mmap_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(k-sk_lock-AF_INET6); lock(&mm->mmap_lock); lock(fs_reclaim); *** DEADLOCK *** 2 locks held by syz.3.3387/17804: #0: ffffffff905e2228 (br_ioctl_mutex){+.+.}-{4:4}, at: br_ioctl_call+0x34/0xa0 net/socket.c:1225 #1: ffff88807ad4b440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline] #1: ffff88807ad4b440 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline] #1: ffff88807ad4b440 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x35/0x6f0 mm/mmap_lock.c:501 stack backtrace: CPU: 0 UID: 0 PID: 17804 Comm: syz.3.3387 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] prepare_alloc_pages+0x166/0x5f0 mm/page_alloc.c:5018 __alloc_frozen_pages_noprof+0x19a/0x2ba0 mm/page_alloc.c:5239 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2484 alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2575 pagetable_alloc_noprof include/linux/mm.h:3404 [inline] pmd_alloc_one_noprof include/asm-generic/pgalloc.h:143 [inline] __pmd_alloc+0x3b/0x9c0 mm/memory.c:6709 pmd_alloc include/linux/mm.h:3320 [inline] __handle_mm_fault+0xa99/0x2b60 mm/memory.c:6406 handle_mm_fault+0x36d/0xa20 mm/memory.c:6623 do_user_addr_fault+0x74c/0x12f0 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:60 Code: 83 f9 08 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 e9 bd 93 04 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 <48> 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 RSP: 0018:ffffc900044e7c18 EFLAGS: 00050202 RAX: 0000000000000001 RBX: 0000000000000008 RCX: 0000000000000028 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc900044e7cd0 RBP: 0000000000000028 R08: 0000000000000001 R09: fffff5200089cf9e R10: ffffc900044e7cf7 R11: 0000000000000001 R12: 0000000000000000 R13: ffffc900044e7cd0 R14: ffffc900044e7cd0 R15: 0000000000000000 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] _inline_copy_from_user include/linux/uaccess.h:185 [inline] _copy_from_user+0x98/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] get_user_ifreq+0x77/0x1c0 net/socket.c:3350 br_ioctl_stub+0x23d/0x4d0 net/bridge/br_ioctl.c:409 br_ioctl_call+0x53/0xa0 net/socket.c:1227 sock_ioctl+0x616/0x6b0 net/socket.c:1329 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9f4239c629 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9f432ed028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9f42616180 RCX: 00007f9f4239c629 RDX: 0000000000000008 RSI: 00000000000089a2 RDI: 0000000000000003 RBP: 00007f9f42432b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9f42616218 R14: 00007f9f42616180 R15: 00007ffd31101248 ---------------- Code disassembly (best guess): 0: 83 f9 08 cmp $0x8,%ecx 3: 73 25 jae 0x2a 5: 85 c9 test %ecx,%ecx 7: 74 0f je 0x18 9: 8a 06 mov (%rsi),%al b: 88 07 mov %al,(%rdi) d: 48 ff c7 inc %rdi 10: 48 ff c6 inc %rsi 13: 48 ff c9 dec %rcx 16: 75 f1 jne 0x9 18: e9 bd 93 04 00 jmp 0x493da 1d: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1) 24: 00 00 00 00 28: 66 90 xchg %ax,%ax * 2a: 48 8b 06 mov (%rsi),%rax <-- trapping instruction 2d: 48 89 07 mov %rax,(%rdi) 30: 48 83 c6 08 add $0x8,%rsi 34: 48 83 c7 08 add $0x8,%rdi 38: 83 e9 08 sub $0x8,%ecx 3b: 74 db je 0x18 3d: 83 f9 08 cmp $0x8,%ecx --- This report is generated by a bot. 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