From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo2-f0.google.com (mail-oo2-f0.google.com [74.125.231.128]) (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 03D05559CBB for ; Tue, 22 Sep 2026 15:03:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.128 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790089407; cv=none; b=n/0nBtTn1HMHudkTO82nrNdB+ktDQHL637mOYUpeWaESg8d5vHcep7UZOqFjL8wMMnNMY32AacEk5hzw4qSIteu4KFb709wHMzoMkgmP6S0co+UMXKzGjUGHg2gNnNuxZJLU25QV33tYdFxTnY6V/rSlchNZNAorK8gdYJUcOvk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790089407; c=relaxed/simple; bh=UFEL4EbqlZlIl2PIgjhTvGMox+QLWc5x/ZYc30QxGhU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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2002:a05:6820:188a:b0:6b7:8415:d78f with SMTP id 006d021491bc7-6ca9ca56035mr12207866eaf.58.1790089374715; Tue, 22 Sep 2026 08:02:54 -0700 (PDT) Date: Tue, 22 Sep 2026 08:02:54 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ab2989e.a6af0033.177e91.0022.GAE@google.com> Subject: [syzbot] [dm?] KASAN: slab-use-after-free Read in dm_table_get_mode From: syzbot To: agk@redhat.com, bmarzins@redhat.com, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org, mpatocka@redhat.com, snitzer@kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 38872197cae2 Merge branch 'for-next/fixes' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=116dd805580000 kernel config: https://syzkaller.appspot.com/x/.config?x=56ed23170c168d4c dashboard link: https://syzkaller.appspot.com/bug?extid=bdff1ecf726d2af66afd compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 userspace arch: arm64 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14e8f805580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17efe805580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/c5963fdd6790/disk-38872197.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a8c2cab00c45/vmlinux-38872197.xz kernel image: https://storage.googleapis.com/syzbot-assets/bde15d173380/Image-38872197.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bdff1ecf726d2af66afd@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in dm_table_get_mode+0x60/0x68 drivers/md/dm-table.c:2121 Read of size 4 at addr ffff0000d75134f4 by task syz.1.7295/2493 CPU: 0 UID: 0 PID: 2493 Comm: syz.1.7295 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xb0/0x238 mm/kasan/report.c:378 print_report+0x68/0x84 mm/kasan/report.c:482 kasan_report+0x8c/0xc4 mm/kasan/report.c:595 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380 dm_table_get_mode+0x60/0x68 drivers/md/dm-table.c:2121 do_resume drivers/md/dm-ioctl.c:1317 [inline] dev_suspend+0x40c/0x750 drivers/md/dm-ioctl.c:1360 ctl_ioctl drivers/md/dm-ioctl.c:2213 [inline] dm_ctl_ioctl+0x884/0xbbc drivers/md/dm-ioctl.c:2235 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 Allocated by task 2493: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:570 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x2f4/0x5fc mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] dm_table_create+0x8c/0x2ac drivers/md/dm-table.c:136 table_load+0x104/0x764 drivers/md/dm-ioctl.c:1631 ctl_ioctl drivers/md/dm-ioctl.c:2213 [inline] dm_ctl_ioctl+0x884/0xbbc drivers/md/dm-ioctl.c:2235 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 Freed by task 2494: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_free_info+0x54/0x6c mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x74/0xa4 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6508 [inline] kfree+0x188/0x698 mm/slub.c:6801 dm_table_destroy+0x32c/0x3a0 drivers/md/dm-table.c:210 do_resume drivers/md/dm-ioctl.c:1341 [inline] dev_suspend+0x5a4/0x750 drivers/md/dm-ioctl.c:1360 ctl_ioctl drivers/md/dm-ioctl.c:2213 [inline] dm_ctl_ioctl+0x884/0xbbc drivers/md/dm-ioctl.c:2235 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 The buggy address belongs to the object at ffff0000d7513400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 244 bytes inside of freed 512-byte region [ffff0000d7513400, ffff0000d7513600) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff0000d7511c00 pfn:0x117510 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x5ffc00000000240(workingset|head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000240 ffff0000c0001c80 fffffdffc3c21e10 fffffdffc35db510 raw: ffff0000d7511c00 000000000010000f 00000000f5000000 0000000000000000 head: 05ffc00000000240 ffff0000c0001c80 fffffdffc3c21e10 fffffdffc35db510 head: ffff0000d7511c00 000000000010000f 00000000f5000000 0000000000000000 head: 05ffc00000000002 fffffdffc35d4401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d7513380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d7513400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000d7513480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d7513500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d7513580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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