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<38a47857-05f4-4322-990e-3d83a7040517@gmail.com> Date: Sun, 31 Oct 2021 12:14:23 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [syzbot] KASAN: use-after-free Write in __io_free_req Content-Language: en-US To: Xiaoguang Wang References: <000000000000fba7bd05cf7eb8f5@google.com> Cc: syzbot , axboe@kernel.dk, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com From: Pavel Begunkov In-Reply-To: <000000000000fba7bd05cf7eb8f5@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/29/21 15:34, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: bdcc9f6a5682 Add linux-next specific files for 20211029 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=12a87e22b00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=cea91ee10b0cd274 > dashboard link: https://syzkaller.appspot.com/bug?extid=78b76ebc91042904f34e > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10cf03e2b00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+78b76ebc91042904f34e@syzkaller.appspotmail.com Hey Xiaoguang, Apparently, this was caused by those 3 dropped poll patches, when you'll be resending would be great if you test with this syz repro as well. > ================================================================== > BUG: KASAN: use-after-free in wq_list_add_head fs/io-wq.h:71 [inline] > BUG: KASAN: use-after-free in __io_free_req+0x33f/0x3c5 fs/io_uring.c:2040 > Write of size 8 at addr ffff8880713ecbb8 by task syz-executor.0/8059 > > CPU: 1 PID: 8059 Comm: syz-executor.0 Not tainted 5.15.0-rc7-next-20211029-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 > print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247 > __kasan_report mm/kasan/report.c:433 [inline] > kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 > wq_list_add_head fs/io-wq.h:71 [inline] > __io_free_req+0x33f/0x3c5 fs/io_uring.c:2040 > tctx_task_work+0x1b3/0x630 fs/io_uring.c:2207 > task_work_run+0xdd/0x1a0 kernel/task_work.c:164 > exit_task_work include/linux/task_work.h:32 [inline] > do_exit+0xc14/0x2b40 kernel/exit.c:832 > do_group_exit+0x125/0x310 kernel/exit.c:929 > get_signal+0x47d/0x21d0 kernel/signal.c:2820 > arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 > handle_signal_work kernel/entry/common.c:148 [inline] > exit_to_user_mode_loop kernel/entry/common.c:172 [inline] > exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 > __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] > syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 > do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7f9da8c4ea39 > Code: Unable to access opcode bytes at RIP 0x7f9da8c4ea0f. > RSP: 002b:00007f9da83a3218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: fffffffffffffe00 RBX: 00007f9da8d62028 RCX: 00007f9da8c4ea39 > RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9da8d62028 > RBP: 00007f9da8d62020 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9da8d6202c > R13: 00007ffd6e91741f R14: 00007f9da83a3300 R15: 0000000000022000 > > > Allocated by task 8059: > kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 > kasan_set_track mm/kasan/common.c:46 [inline] > set_alloc_info mm/kasan/common.c:434 [inline] > __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 > kasan_slab_alloc include/linux/kasan.h:259 [inline] > slab_post_alloc_hook mm/slab.h:519 [inline] > kmem_cache_alloc_bulk+0x39d/0x720 mm/slub.c:3730 > __io_alloc_req_refill fs/io_uring.c:1977 [inline] > io_alloc_req_refill fs/io_uring.c:2003 [inline] > io_submit_sqes.cold+0x20b/0x43d fs/io_uring.c:7325 > __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10052 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Freed by task 1041: > kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 > kasan_set_track+0x21/0x30 mm/kasan/common.c:46 > kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 > ____kasan_slab_free mm/kasan/common.c:366 [inline] > ____kasan_slab_free mm/kasan/common.c:328 [inline] > __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 > kasan_slab_free include/linux/kasan.h:235 [inline] > slab_free_hook mm/slub.c:1723 [inline] > slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 > slab_free mm/slub.c:3513 [inline] > kmem_cache_free+0x92/0x5e0 mm/slub.c:3529 > io_req_caches_free+0x1aa/0x1e6 fs/io_uring.c:9291 > io_ring_exit_work+0x1e4/0xbe8 fs/io_uring.c:9467 > process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 > worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 > kthread+0x405/0x4f0 kernel/kthread.c:327 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 > > The buggy address belongs to the object at ffff8880713ecb40 > which belongs to the cache io_kiocb of size 224 > The buggy address is located 120 bytes inside of > 224-byte region [ffff8880713ecb40, ffff8880713ecc20) > The buggy address belongs to the page: > page:ffffea0001c4fb00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880713ec8c0 pfn:0x713ec > flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) > raw: 00fff00000000200 ffffea0001c4d400 dead000000000004 ffff88814607bdc0 > raw: ffff8880713ec8c0 00000000800c000b 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 7168, ts 1580559391621, free_ts 1580537948913 > prep_new_page mm/page_alloc.c:2418 [inline] > get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149 > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369 > alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191 > alloc_slab_page mm/slub.c:1793 [inline] > allocate_slab mm/slub.c:1930 [inline] > new_slab+0x32d/0x4a0 mm/slub.c:1993 > ___slab_alloc+0x918/0xfe0 mm/slub.c:3022 > kmem_cache_alloc_bulk+0x21a/0x720 mm/slub.c:3706 > __io_alloc_req_refill fs/io_uring.c:1977 [inline] > io_alloc_req_refill fs/io_uring.c:2003 [inline] > io_submit_sqes.cold+0x20b/0x43d fs/io_uring.c:7325 > __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10052 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > page last free stack trace: > reset_page_owner include/linux/page_owner.h:24 [inline] > free_pages_prepare mm/page_alloc.c:1338 [inline] > free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389 > free_unref_page_prepare mm/page_alloc.c:3309 [inline] > free_unref_page_list+0x1a9/0xfa0 mm/page_alloc.c:3425 > release_pages+0x3f4/0x1480 mm/swap.c:979 > tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] > tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] > tlb_flush_mmu mm/mmu_gather.c:249 [inline] > tlb_finish_mmu+0x165/0x8c0 mm/mmu_gather.c:340 > exit_mmap+0x1ea/0x630 mm/mmap.c:3173 > __mmput+0x122/0x4b0 kernel/fork.c:1164 > mmput+0x56/0x60 kernel/fork.c:1185 > exit_mm kernel/exit.c:507 [inline] > do_exit+0xb27/0x2b40 kernel/exit.c:819 > do_group_exit+0x125/0x310 kernel/exit.c:929 > get_signal+0x47d/0x21d0 kernel/signal.c:2820 > arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 > handle_signal_work kernel/entry/common.c:148 [inline] > exit_to_user_mode_loop kernel/entry/common.c:172 [inline] > exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 > __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] > syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 > do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Memory state around the buggy address: > ffff8880713eca80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc > ffff8880713ecb00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >> ffff8880713ecb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8880713ecc00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc > ffff8880713ecc80: 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. > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches > -- Pavel Begunkov