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-0700 (PDT) Date: Wed, 27 Jul 2022 19:46:13 -0700 In-Reply-To: <20220728022854.432-1-hdanton@sina.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000072ba8605e4d48900@google.com> Subject: Re: [syzbot] KASAN: use-after-free Read in __post_watch_notification From: syzbot To: hdanton@sina.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: KASAN: use-after-free Read in __post_watch_notification ================================================================== BUG: KASAN: use-after-free in __post_watch_notification+0x1fe/0x900 kernel/watch_queue.c:221 Read of size 8 at addr ffff888021dc5410 by task syz-executor239/27731 CPU: 0 PID: 27731 Comm: syz-executor239 Not tainted 5.19.0-rc8-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_address_description+0x65/0x4b0 mm/kasan/report.c:313 print_report+0xf4/0x210 mm/kasan/report.c:429 kasan_report+0xfb/0x130 mm/kasan/report.c:491 __post_watch_notification+0x1fe/0x900 kernel/watch_queue.c:221 post_watch_notification include/linux/watch_queue.h:109 [inline] notify_key security/keys/internal.h:199 [inline] __key_update+0x428/0x4e0 security/keys/key.c:775 key_create_or_update+0xa8f/0xd60 security/keys/key.c:979 __do_sys_add_key security/keys/keyctl.c:134 [inline] __se_sys_add_key+0x338/0x480 security/keys/keyctl.c:74 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f503a6db9f9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f503a68d2f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8 RAX: ffffffffffffffda RBX: 00007f503a763408 RCX: 00007f503a6db9f9 RDX: 00000000200000c0 RSI: 0000000020000080 RDI: 0000000020000040 RBP: 0000000000000000 R08: 00000000fffffffc R09: 0000000000000000 R10: 0000000000000048 R11: 0000000000000246 R12: 00007f503a763400 R13: 00007f503a76340c R14: 00007f503a731064 R15: 3a74707972637366 Allocated by task 27707: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:515 kasan_kmalloc include/linux/kasan.h:234 [inline] kmem_cache_alloc_trace+0x94/0x310 mm/slub.c:3284 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] watch_queue_init+0x4f/0x140 kernel/watch_queue.c:674 create_pipe_files+0x478/0x6e0 fs/pipe.c:921 __do_pipe_flags+0x46/0x200 fs/pipe.c:962 do_pipe2+0xd0/0x300 fs/pipe.c:1010 __do_sys_pipe2 fs/pipe.c:1028 [inline] __se_sys_pipe2 fs/pipe.c:1026 [inline] __x64_sys_pipe2+0x56/0x60 fs/pipe.c:1026 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 22: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4c/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0xd8/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1754 [inline] slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1780 slab_free mm/slub.c:3536 [inline] kmem_cache_free_bulk+0x105/0x1d0 mm/slub.c:3683 kfree_bulk include/linux/slab.h:456 [inline] kfree_rcu_work+0x35b/0x7c0 kernel/rcu/tree.c:3370 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:348 kvfree_call_rcu+0x118/0x840 kernel/rcu/tree.c:3647 keyctl_watch_key+0x3d2/0x450 security/keys/keyctl.c:1839 __do_sys_keyctl security/keys/keyctl.c:2016 [inline] __se_sys_keyctl+0x635/0xb60 security/keys/keyctl.c:1869 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888021dc5400 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 16 bytes inside of 192-byte region [ffff888021dc5400, ffff888021dc54c0) The buggy address belongs to the physical page: page:ffffea0000877140 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21dc5 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888011c41a00 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 27704, tgid 27703 (syz-executor239), ts 435095125439, free_ts 435075154261 prep_new_page mm/page_alloc.c:2456 [inline] get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4198 __alloc_pages+0x259/0x560 mm/page_alloc.c:5426 alloc_slab_page+0x70/0xf0 mm/slub.c:1824 allocate_slab+0x5e/0x520 mm/slub.c:1969 new_slab mm/slub.c:2029 [inline] ___slab_alloc+0x42e/0xce0 mm/slub.c:3031 __slab_alloc mm/slub.c:3118 [inline] slab_alloc_node mm/slub.c:3209 [inline] slab_alloc mm/slub.c:3251 [inline] kmem_cache_alloc_trace+0x25c/0x310 mm/slub.c:3282 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] loopback_open+0x120/0xa20 sound/drivers/aloop.c:1192 snd_pcm_open_substream+0xd8b/0x1b70 sound/core/pcm_native.c:2739 snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2454 [inline] snd_pcm_oss_open+0x1185/0x2060 sound/core/oss/pcm_oss.c:2535 chrdev_open+0x5fb/0x680 fs/char_dev.c:414 do_dentry_open+0x789/0x1040 fs/open.c:848 do_open fs/namei.c:3520 [inline] path_openat+0x26c0/0x2ec0 fs/namei.c:3653 do_filp_open+0x277/0x4f0 fs/namei.c:3680 do_sys_openat2+0x13b/0x500 fs/open.c:1278 do_sys_open fs/open.c:1294 [inline] __do_sys_openat fs/open.c:1310 [inline] __se_sys_openat fs/open.c:1305 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1305 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1371 [inline] free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1421 free_unref_page_prepare mm/page_alloc.c:3343 [inline] free_unref_page+0x7d/0x390 mm/page_alloc.c:3438 __vunmap+0x867/0x9d0 mm/vmalloc.c:2665 do_free_pages sound/core/pcm_memory.c:65 [inline] snd_pcm_lib_free_pages+0x213/0x2e0 sound/core/pcm_memory.c:467 do_hw_free sound/core/pcm_native.c:876 [inline] snd_pcm_release_substream+0x2cd/0x490 sound/core/pcm_native.c:2704 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2413 [inline] snd_pcm_oss_release+0x1a3/0x270 sound/core/oss/pcm_oss.c:2592 __fput+0x3b9/0x820 fs/file_table.c:317 task_work_run+0x146/0x1c0 kernel/task_work.c:177 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x134/0x160 kernel/entry/common.c:169 exit_to_user_mode_prepare+0xad/0x110 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x2e/0x60 kernel/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff888021dc5300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888021dc5380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff888021dc5400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888021dc5480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888021dc5500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Tested on: commit: e0dccc3b Linux 5.19-rc8 git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=123a0752080000 kernel config: https://syzkaller.appspot.com/x/.config?x=cfd2f9ae77f1f719 dashboard link: https://syzkaller.appspot.com/bug?extid=03d7b43290037d1f87ca compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 patch: https://syzkaller.appspot.com/x/patch.diff?x=17cb2102080000