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with SMTP id 006d021491bc7-65d0ea97125mr804653eaf.41.1766114540494; Thu, 18 Dec 2025 19:22:20 -0800 (PST) Date: Thu, 18 Dec 2025 19:22:20 -0800 In-Reply-To: <69296521.a70a0220.d98e3.0135.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6944c4ec.a70a0220.207337.00ff.GAE@google.com> Subject: Forwarded: Re: [syzbot] [io-uring?] KASAN: slab-use-after-free Read in io_poll_remove_entries (2) From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: [syzbot] [io-uring?] KASAN: slab-use-after-free Read in io_pol= l_remove_entries (2) Author: axboe@kernel.dk #syz invalid On Fri, Nov 28, 2025 at 2:02=E2=80=AFAM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: ef68bf704646 Add linux-next specific files for 20251127 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=3D113a9e9258000= 0 > kernel config: https://syzkaller.appspot.com/x/.config?x=3D75e4ba9be1d3d= 04 > dashboard link: https://syzkaller.appspot.com/bug?extid=3D721cddf31614335= 3975e > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b797= 6-1~exp1~20250708183702.136), Debian LLD 20.1.8 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/d2c8379aac84/dis= k-ef68bf70.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/c5f8945ec4ba/vmlinu= x-ef68bf70.xz > kernel image: https://storage.googleapis.com/syzbot-assets/dab0de6e99a6/b= zImage-ef68bf70.xz > > IMPORTANT: if you fix the issue, please add the following tag to the comm= it: > Reported-by: syzbot+721cddf316143353975e@syzkaller.appspotmail.com > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > BUG: KASAN: slab-use-after-free in __raw_spin_lock_irq include/linux/spin= lock_api_smp.h:119 [inline] > BUG: KASAN: slab-use-after-free in _raw_spin_lock_irq+0xa2/0xf0 kernel/lo= cking/spinlock.c:170 > Read of size 1 at addr ffff88801c7f2d50 by task kworker/0:8/5987 > > CPU: 0 UID: 0 PID: 5987 Comm: kworker/0:8 Not tainted syzkaller #0 PREEMP= T(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS G= oogle 10/25/2025 > Workqueue: events io_fallback_req_func > Call Trace: > > dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 > print_address_description mm/kasan/report.c:378 [inline] > print_report+0xca/0x240 mm/kasan/report.c:482 > kasan_report+0x118/0x150 mm/kasan/report.c:595 > __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:573 > kasan_check_byte include/linux/kasan.h:401 [inline] > lock_acquire+0x84/0x340 kernel/locking/lockdep.c:5842 > __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] > _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170 > spin_lock_irq include/linux/spinlock.h:376 [inline] > io_poll_remove_entry io_uring/poll.c:146 [inline] > io_poll_remove_entries+0x1eb/0x620 io_uring/poll.c:179 > io_poll_task_func+0x6f6/0xd10 io_uring/poll.c:325 > io_fallback_req_func+0x126/0x210 io_uring/io_uring.c:246 > process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261 > process_scheduled_works kernel/workqueue.c:3344 [inline] > worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425 > kthread+0x711/0x8a0 kernel/kthread.c:463 > ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 > > > Allocated by task 10303: > kasan_save_stack mm/kasan/common.c:56 [inline] > kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 > unpoison_slab_object mm/kasan/common.c:339 [inline] > __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365 > kasan_slab_alloc include/linux/kasan.h:252 [inline] > slab_post_alloc_hook mm/slub.c:4948 [inline] > slab_alloc_node mm/slub.c:5258 [inline] > kmem_cache_alloc_lru_noprof+0x36c/0x6e0 mm/slub.c:5277 > mqueue_alloc_inode+0x28/0x40 ipc/mqueue.c:502 > alloc_inode+0x6a/0x1b0 fs/inode.c:346 > new_inode+0x22/0x170 fs/inode.c:1175 > mqueue_get_inode+0x27/0xb50 ipc/mqueue.c:297 > mqueue_create_attr+0x1ac/0x2e0 ipc/mqueue.c:590 > vfs_mkobj+0xcf/0x290 fs/namei.c:4153 > prepare_open ipc/mqueue.c:876 [inline] > mqueue_file_open ipc/mqueue.c:905 [inline] > do_mq_open+0x60d/0x7c0 ipc/mqueue.c:928 > __do_sys_mq_open ipc/mqueue.c:941 [inline] > __se_sys_mq_open ipc/mqueue.c:934 [inline] > __x64_sys_mq_open+0x16a/0x1c0 ipc/mqueue.c:934 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Freed by task 0: > kasan_save_stack mm/kasan/common.c:56 [inline] > kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 > kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 > poison_slab_object mm/kasan/common.c:252 [inline] > __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 > kasan_slab_free include/linux/kasan.h:234 [inline] > slab_free_hook mm/slub.c:2540 [inline] > slab_free mm/slub.c:6663 [inline] > kmem_cache_free+0x197/0x620 mm/slub.c:6774 > rcu_do_batch kernel/rcu/tree.c:2605 [inline] > rcu_core+0xd70/0x1870 kernel/rcu/tree.c:2857 > handle_softirqs+0x27d/0x850 kernel/softirq.c:626 > __do_softirq kernel/softirq.c:660 [inline] > invoke_softirq kernel/softirq.c:496 [inline] > __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727 > irq_exit_rcu+0x9/0x30 kernel/softirq.c:743 > instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inli= ne] > sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.= h:697 > > Last potentially related work creation: > kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 > kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 > __call_rcu_common kernel/rcu/tree.c:3119 [inline] > call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3239 > destroy_inode fs/inode.c:401 [inline] > evict+0x931/0xae0 fs/inode.c:861 > __dentry_kill+0x209/0x660 fs/dcache.c:670 > finish_dput+0xc9/0x480 fs/dcache.c:879 > __fput+0x68e/0xa70 fs/file_table.c:476 > task_work_run+0x1d4/0x260 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:44 [inline] > exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75 > __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_work include/linux/entry-common.h:159 [inline] > syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] > do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > The buggy address belongs to the object at ffff88801c7f2880 > which belongs to the cache mqueue_inode_cache of size 1576 > The buggy address is located 1232 bytes inside of > freed 1576-byte region [ffff88801c7f2880, ffff88801c7f2ea8) > > The buggy address belongs to the physical page: > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88801c7f= 1440 pfn:0x1c7f0 > head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > memcg:ffff88802ea71f01 > flags: 0xfff00000000040(head|node=3D0|zone=3D1|lastcpupid=3D0x7ff) > page_type: f5(slab) > raw: 00fff00000000040 ffff88801cf88c80 dead000000000122 0000000000000000 > raw: ffff88801c7f1440 000000008012000e 00000000f5000000 ffff88802ea71f01 > head: 00fff00000000040 ffff88801cf88c80 dead000000000122 0000000000000000 > head: ffff88801c7f1440 000000008012000e 00000000f5000000 ffff88802ea71f01 > head: 00fff00000000003 ffffea000071fc01 00000000ffffffff 00000000ffffffff > head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(= __GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), = pid 1, tgid 1 (swapper/0), ts 9112271990, free_ts 0 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 > prep_new_page mm/page_alloc.c:1854 [inline] > get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 > __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 > alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 > alloc_slab_page mm/slub.c:3075 [inline] > allocate_slab+0x86/0x3b0 mm/slub.c:3248 > new_slab mm/slub.c:3302 [inline] > ___slab_alloc+0xf2b/0x1960 mm/slub.c:4651 > __slab_alloc+0x65/0x100 mm/slub.c:4774 > __slab_alloc_node mm/slub.c:4850 [inline] > slab_alloc_node mm/slub.c:5246 [inline] > kmem_cache_alloc_lru_noprof+0x3fe/0x6e0 mm/slub.c:5277 > mqueue_alloc_inode+0x28/0x40 ipc/mqueue.c:502 > alloc_inode+0x6a/0x1b0 fs/inode.c:346 > new_inode+0x22/0x170 fs/inode.c:1175 > mqueue_get_inode ipc/mqueue.c:297 [inline] > mqueue_fill_super+0xdc/0x380 ipc/mqueue.c:416 > vfs_get_super fs/super.c:1324 [inline] > get_tree_nodev+0xbb/0x150 fs/super.c:1343 > vfs_get_tree+0x92/0x2a0 fs/super.c:1751 > fc_mount fs/namespace.c:1209 [inline] > fc_mount_longterm+0x1c/0x100 fs/namespace.c:1220 > mq_create_mount ipc/mqueue.c:486 [inline] > mq_init_ns+0x275/0x360 ipc/mqueue.c:1639 > page_owner free stack trace missing > > Memory state around the buggy address: > ffff88801c7f2c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88801c7f2c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff88801c7f2d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88801c7f2d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88801c7f2e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup