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Date: Thu, 17 Feb 2022 17:06:45 -0800
From: John Hubbard <jhubbard@...dia.com>
To: Lee Jones <lee.jones@...aro.org>, linux-ext4@...r.kernel.org
Cc: Christoph Hellwig <hch@....de>, Dave Chinner <dchinner@...hat.com>,
Goldwyn Rodrigues <rgoldwyn@...e.com>,
"Darrick J . Wong" <darrick.wong@...cle.com>,
Bob Peterson <rpeterso@...hat.com>,
Damien Le Moal <damien.lemoal@....com>,
Theodore Ts'o <tytso@....edu>,
Andreas Gruenbacher <agruenba@...hat.com>,
Ritesh Harjani <riteshh@...ux.ibm.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Johannes Thumshirn <jth@...nel.org>, linux-xfs@...r.kernel.org,
linux-fsdevel@...r.kernel.org, cluster-devel@...hat.com,
linux-kernel@...r.kernel.org
Subject: Re: [REPORT] kernel BUG at fs/ext4/inode.c:2620 - page_buffers()
On 2/16/22 08:31, Lee Jones wrote:
> Good afternoon,
...
> I managed to seemingly bisect the issue down to commit:
>
> 60263d5889e6d ("iomap: fall back to buffered writes for invalidation failures")
>
> Although it appears to be the belief of the Filesystem community that
> this is likely not the cause of the issue and should therefore not be
> reverted.
They are correct in this matter, imho. :)
...
> Darrick seems to suggest that:
>
> "The BUG report came from page_buffers failing to find any buffer heads
> attached to the page."
Yes. And looking at the pair of backtraces below, this looks very much
like another aspect of the "get_user_pages problem" [1], originally
described in Jan Kara's 2018 email [2].
I'm getting close to posting an RFC for the direct IO conversion to
FOLL_PIN, but even after that, various parts of the kernel (reclaim,
filesystems/block layer) still need to be changed so as to use
page_maybe_dma_pinned() to help avoid this problem. There's a bit
more than that, actually.
[1] https://lwn.net/Articles/753027/
[2] https://www.spinics.net/lists/linux-mm/msg142700.html
thanks,
--
John Hubbard
NVIDIA
>
> If the reproducer, also massively stripped down from the original
> report, would be of any use to you, it can be found further down at
> [2].
>
> I don't how true this is, but it is my current belief that user-space
> should not be able to force the kernel to BUG. This seems to be a
> temporary DoS issue. So although not a critically serious security
> problem involved memory leakage or data corruption, it could
> potentially cause a nuisance if not rectified.
>
> Any well meaning help with this would be gratefully received.
>
> Kind regards,
> Lee
>
> [0] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fbug%3Fextid%3D41c966bf0729a530bd8d&data=04%7C01%7Cjhubbard%40nvidia.com%7C107e857de4b940fbe7e708d9f169d4a8%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637806259852035011%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=5oD2%2BB9iOOSqSh3xwLLzR1vFxqyMtYNivJVQmepj2ww%3D&reserved=0
>
> [1]
> [ 15.200920] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 15.215877] File: /syzkaller.IsS3Yc/0/bus PID: 1497 Comm: repro
> [ 16.718970] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 16.734250] File: /syzkaller.IsS3Yc/5/bus PID: 1512 Comm: repro
> [ 17.013871] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 17.028193] File: /syzkaller.IsS3Yc/6/bus PID: 1515 Comm: repro
> [ 17.320498] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 17.336115] File: /syzkaller.IsS3Yc/7/bus PID: 1518 Comm: repro
> [ 17.617921] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 17.633063] File: /syzkaller.IsS3Yc/8/bus PID: 1521 Comm: repro
> [ 18.527260] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 18.544236] File: /syzkaller.IsS3Yc/11/bus PID: 1530 Comm: repro
> [ 18.810347] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 18.824721] File: /syzkaller.IsS3Yc/12/bus PID: 1533 Comm: repro
> [ 19.099315] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 19.114151] File: /syzkaller.IsS3Yc/13/bus PID: 1536 Comm: repro
> [ 19.403882] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 19.418467] File: /syzkaller.IsS3Yc/14/bus PID: 1539 Comm: repro
> [ 19.703934] Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!
> [ 19.718400] File: /syzkaller.IsS3Yc/15/bus PID: 1542 Comm: repro
> [ 26.533129] ------------[ cut here ]------------
> [ 26.540473] WARNING: CPU: 1 PID: 1612 at fs/ext4/inode.c:3576 ext4_set_page_dirty+0xaf/0xc0
> [ 26.553171] Modules linked in:
> [ 26.557354] CPU: 1 PID: 1612 Comm: repro Not tainted 5.16.0+ #169
> [ 26.565238] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> [ 26.576182] RIP: 0010:ext4_set_page_dirty+0xaf/0xc0
> [ 26.583077] Code: 4c 89 ff e8 e3 86 e7 ff 49 f7 07 00 20 00 00 74 19 4c 89 ff 5b 41 5e 41 5f e9 8d 05 f0 ff 48 83 c0 ff 48 89 c3 e9 76 ff ff ff <0f> 0b eb e3 48 83 c0 ff 48 89 c3 eb 9e 0f 0b eb b8 55 48 89 e5 41
> [ 26.607402] RSP: 0018:ffff88810f4ffa10 EFLAGS: 00010246
> [ 26.614646] RAX: ffffea00043bc687 RBX: ffffea00043bc680 RCX: ffffffff9913f86d
> [ 26.625115] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffffea00043bc680
> [ 26.635137] RBP: 0000000000000400 R08: dffffc0000000000 R09: fffff940008778d1
> [ 26.644923] R10: fffff940008778d1 R11: 0000000000000000 R12: ffff88810e14c000
> [ 26.654807] R13: ffffea00043bc680 R14: ffffea00043bc688 R15: ffffea00043bc680
> [ 26.664812] FS: 00007f27c16d6640(0000) GS:ffff8883ef440000(0000) knlGS:0000000000000000
> [ 26.676238] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 26.684212] CR2: 000000000049b3a8 CR3: 000000010f7a6005 CR4: 0000000000370ee0
> [ 26.693896] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 26.703778] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 26.714238] Call Trace:
> [ 26.717987] <TASK>
> [ 26.721105] folio_mark_dirty+0x72/0xa0
> [ 26.726455] set_page_dirty_lock+0x4a/0x70
> [ 26.732426] unpin_user_pages_dirty_lock+0x101/0x1d0
> [ 26.739369] process_vm_rw_single_vec+0x2f4/0x3c0
> [ 26.745707] ? process_vm_rw+0x4d0/0x4d0
> [ 26.751454] ? mm_access+0xe1/0x120
> [ 26.756495] process_vm_rw+0x2fd/0x4d0
> [ 26.762431] ? __ia32_sys_process_vm_writev+0x80/0x80
> [ 26.769780] ? preempt_count_sub+0xf/0xc0
> [ 26.775021] ? folio_add_lru+0xea/0x110
> [ 26.780260] ? preempt_count_sub+0xf/0xc0
> [ 26.786062] ? _raw_spin_unlock+0x2e/0x50
> [ 26.791676] ? __handle_mm_fault+0x14a7/0x1970
> [ 26.797550] ? handle_mm_fault+0x1d0/0x1d0
> [ 26.802981] ? up_read+0x6f/0x180
> [ 26.807430] ? down_read_trylock+0x13f/0x190
> [ 26.813252] ? down_write_trylock+0x130/0x130
> [ 26.818935] ? handle_mm_fault+0x160/0x1d0
> [ 26.824454] ? do_kern_addr_fault+0x130/0x130
> [ 26.830695] __x64_sys_process_vm_writev+0x71/0x80
> [ 26.837270] do_syscall_64+0x43/0x90
> [ 26.842134] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 26.848994] RIP: 0033:0x44c849
> [ 26.853311] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 14 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
> [ 26.877911] RSP: 002b:00007f27c16d6168 EFLAGS: 00000216 ORIG_RAX: 0000000000000137
> [ 26.887953] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000044c849
> [ 26.897571] RDX: 0000000000000001 RSI: 0000000020c22000 RDI: 0000000000000076
> [ 26.907068] RBP: 00007f27c16d61a0 R08: 0000000000000001 R09: 0000000000000000
> [ 26.916433] R10: 0000000020c22fa0 R11: 0000000000000216 R12: 00007ffd3062431e
> [ 26.927113] R13: 00007ffd3062431f R14: 0000000000000000 R15: 00007f27c16d6640
> [ 26.936755] </TASK>
> [ 26.939785] ---[ end trace 42b5bb79157828eb ]---
> [ 27.160243] ------------[ cut here ]------------
> [ 27.166572] kernel BUG at fs/ext4/inode.c:2620!
> [ 27.173362] invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
> [ 27.180459] CPU: 1 PID: 1616 Comm: repro Tainted: G W 5.16.0+ #169
> [ 27.190304] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> [ 27.201112] RIP: 0010:mpage_prepare_extent_to_map+0x573/0x580
> [ 27.208692] Code: 08 14 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 40 01 00 00 75 15 89 d8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b 0f 0b e8 04 39 15 01 0f 1f 40 00 55 48 89 e5 41 57 41 56 41
> [ 27.232612] RSP: 0018:ffff88810f7e6b60 EFLAGS: 00010246
> [ 27.239348] RAX: ffffea00043b4fc7 RBX: 0000000000000067 RCX: ffffffff9913ea61
> [ 27.248720] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffffea00043b4fc0
> [ 27.257899] RBP: ffff88810f7e6cf0 R08: dffffc0000000000 R09: fffff940008769f9
> [ 27.266846] R10: fffff940008769f9 R11: 0000000000000000 R12: 0000000000000000
> [ 27.276050] R13: ffff88810f7e6be0 R14: ffffea00043b4fc0 R15: ffff88810f7e6f58
> [ 27.285119] FS: 00007f27c16d6640(0000) GS:ffff8883ef440000(0000) knlGS:0000000000000000
> [ 27.295466] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 27.302935] CR2: 0000000020002002 CR3: 000000010cb70006 CR4: 0000000000370ee0
> [ 27.312837] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 27.322697] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 27.332451] Call Trace:
> [ 27.336060] <TASK>
> [ 27.339164] ? ext4_iomap_swap_activate+0x10/0x10
> [ 27.346171] ? preempt_count_sub+0xf/0xc0
> [ 27.352456] ? page_writeback_cpu_online+0x1f0/0x1f0
> [ 27.359598] ? ext4_init_io_end+0x18/0x90
> [ 27.365427] ? kmem_cache_alloc+0xf2/0x200
> [ 27.371638] ext4_writepages+0x823/0x1c50
> [ 27.377047] ? kernel_text_address+0xa8/0xc0
> [ 27.382587] ? unwind_get_return_address+0x25/0x40
> [ 27.388649] ? __rcu_read_unlock+0x8d/0x320
> [ 27.394134] ? __rcu_read_lock+0x20/0x20
> [ 27.399094] ? preempt_count_sub+0xf/0xc0
> [ 27.404220] ? ext4_readpage+0x110/0x110
> [ 27.409494] ? stack_trace_save+0x120/0x120
> [ 27.414838] ? __is_insn_slot_addr+0x58/0x60
> [ 27.420186] ? kernel_text_address+0xa8/0xc0
> [ 27.425531] ? __kernel_text_address+0x9/0x40
> [ 27.431355] ? unwind_get_return_address+0x25/0x40
> [ 27.437415] ? stack_trace_save+0xdb/0x120
> [ 27.442722] ? stack_trace_snprint+0xc0/0xc0
> [ 27.448310] do_writepages+0x20b/0x3a0
> [ 27.453245] ? __kasan_slab_alloc+0x43/0xb0
> [ 27.458532] ? filter_irq_stacks+0x3d/0x80
> [ 27.463792] ? __writepage+0xb0/0xb0
> [ 27.468366] ? __iomap_dio_rw+0x1c2/0xec0
> [ 27.473579] ? iomap_dio_rw+0x5/0x30
> [ 27.478152] ? ext4_file_write_iter+0x8a8/0xde0
> [ 27.484091] ? do_iter_readv_writev+0x2ce/0x360
> [ 27.490002] ? do_iter_write+0x109/0x370
> [ 27.495400] ? iter_file_splice_write+0x4b6/0x770
> [ 27.501658] ? direct_splice_actor+0x7b/0x90
> [ 27.507225] ? splice_direct_to_actor+0x309/0x570
> [ 27.513487] ? do_splice_direct+0x172/0x230
> [ 27.519352] ? do_sendfile+0x567/0x960
> [ 27.524605] ? __x64_sys_sendfile64+0x104/0x150
> [ 27.531035] ? do_syscall_64+0x43/0x90
> [ 27.536259] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 27.543606] ? do_syscall_64+0x43/0x90
> [ 27.548942] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 27.556281] ? _raw_spin_lock+0x120/0x120
> [ 27.561984] ? __ext4_handle_dirty_metadata+0x22d/0x510
> [ 27.569186] filemap_write_and_wait_range+0x200/0x230
> [ 27.576185] ? filemap_range_needs_writeback+0x400/0x400
> [ 27.583632] ? ext4_mark_iloc_dirty+0x66c/0x6b0
> [ 27.589986] ? kmem_cache_alloc_trace+0xe7/0x230
> [ 27.596373] ? __iomap_dio_rw+0x1c2/0xec0
> [ 27.601967] __iomap_dio_rw+0x525/0xec0
> [ 27.609616] ? jbd2_journal_stop+0x481/0x5b0
> [ 27.615606] ? iomap_dio_complete+0x2a0/0x2a0
> [ 27.622054] ? generic_update_time+0xde/0x130
> [ 27.628225] ? __mnt_drop_write_file+0xd/0x60
> [ 27.634306] ? file_update_time+0x1cd/0x210
> [ 27.640161] ? kernel_text_address+0xa8/0xc0
> [ 27.646114] ? file_remove_privs+0x2b0/0x2b0
> [ 27.652278] iomap_dio_rw+0x5/0x30
> [ 27.657149] ext4_file_write_iter+0x8a8/0xde0
> [ 27.663323] ? ext4_file_read_iter+0x1e0/0x1e0
> [ 27.669800] ? ____kasan_kmalloc+0xd1/0xf0
> [ 27.675676] ? direct_splice_actor+0x7b/0x90
> [ 27.681778] ? splice_direct_to_actor+0x309/0x570
> [ 27.688357] ? do_splice_direct+0x172/0x230
> [ 27.694256] ? do_sendfile+0x567/0x960
> [ 27.699605] ? __x64_sys_sendfile64+0x104/0x150
> [ 27.706129] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 27.713462] do_iter_readv_writev+0x2ce/0x360
> [ 27.719894] ? generic_file_rw_checks+0xd0/0xd0
> [ 27.726446] ? memcpy+0x3c/0x60
> [ 27.731234] ? security_file_permission+0x47/0x270
> [ 27.738026] do_iter_write+0x109/0x370
> [ 27.743417] iter_file_splice_write+0x4b6/0x770
> [ 27.749824] ? splice_from_pipe+0x170/0x170
> [ 27.755630] ? generic_file_splice_read+0x2d0/0x380
> [ 27.765041] ? splice_shrink_spd+0x40/0x40
> [ 27.770668] ? is_mmconf_reserved+0x240/0x240
> [ 27.776487] ? kcalloc+0x1b/0x20
> [ 27.780737] ? splice_from_pipe+0x170/0x170
> [ 27.786278] direct_splice_actor+0x7b/0x90
> [ 27.791885] splice_direct_to_actor+0x309/0x570
> [ 27.797680] ? do_splice_direct+0x230/0x230
> [ 27.803067] ? pipe_to_sendpage+0x1b0/0x1b0
> [ 27.808395] ? security_file_permission+0x47/0x270
> [ 27.814761] do_splice_direct+0x172/0x230
> [ 27.819842] ? splice_direct_to_actor+0x570/0x570
> [ 27.825936] ? security_file_permission+0x47/0x270
> [ 27.832354] do_sendfile+0x567/0x960
> [ 27.837426] ? do_pwritev+0x3d0/0x3d0
> [ 27.842258] ? __se_sys_futex+0x1b1/0x2c0
> [ 27.847619] ? restore_fpregs_from_fpstate+0xc4/0x190
> [ 27.854277] __x64_sys_sendfile64+0x104/0x150
> [ 27.859919] ? __ia32_sys_sendfile+0x170/0x170
> [ 27.865622] ? switch_fpu_return+0x97/0x120
> [ 27.871204] do_syscall_64+0x43/0x90
> [ 27.875661] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 27.882673] RIP: 0033:0x44c849
> [ 27.887077] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 14 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
> [ 27.911882] RSP: 002b:00007f27c16d6178 EFLAGS: 00000203 ORIG_RAX: 0000000000000028
> [ 27.921306] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000044c849
> [ 27.930587] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
> [ 27.939877] RBP: 00007f27c16d61a0 R08: 0000000000000000 R09: 0000000000000000
> [ 27.949975] R10: 0000000080000005 R11: 0000000000000203 R12: 00007ffd3062431e
> [ 27.959298] R13: 00007ffd3062431f R14: 0000000000000000 R15: 00007f27c16d6640
> [ 27.968616] </TASK>
> [ 27.971668] Modules linked in:
> [ 27.975922] ---[ end trace 42b5bb79157828ec ]---
> [ 27.982710] RIP: 0010:mpage_prepare_extent_to_map+0x573/0x580
> [ 27.990558] Code: 08 14 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 40 01 00 00 75 15 89 d8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b 0f 0b e8 04 39 15 01 0f 1f 40 00 55 48 89 e5 41 57 41 56 41
> [ 28.015009] RSP: 0018:ffff88810f7e6b60 EFLAGS: 00010246
> [ 28.021763] RAX: ffffea00043b4fc7 RBX: 0000000000000067 RCX: ffffffff9913ea61
> [ 28.031325] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffffea00043b4fc0
> [ 28.040622] RBP: ffff88810f7e6cf0 R08: dffffc0000000000 R09: fffff940008769f9
> [ 28.050140] R10: fffff940008769f9 R11: 0000000000000000 R12: 0000000000000000
> [ 28.059313] R13: ffff88810f7e6be0 R14: ffffea00043b4fc0 R15: ffff88810f7e6f58
> [ 28.068502] FS: 00007f27c16d6640(0000) GS:ffff8883ef440000(0000) knlGS:0000000000000000
> [ 28.079454] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 28.087279] CR2: 0000000020002002 CR3: 000000010cb70006 CR4: 0000000000370ee0
> [ 28.096763] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 28.105974] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
> [2]
> // https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fbug%3Fid%3D906354c4596539d9561ee6cb6d8c54cda38fc3c2&data=04%7C01%7Cjhubbard%40nvidia.com%7C107e857de4b940fbe7e708d9f169d4a8%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637806259852035011%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=WhaMEtC2yWJva1OO%2Fp0BIYRwADAlClWQPee7Trf9DpQ%3D&reserved=0
> // autogenerated by syzkaller (https://github.com/google/syzkaller)
>
> #define _GNU_SOURCE
>
> #include <arpa/inet.h>
> #include <dirent.h>
> #include <endian.h>
> #include <errno.h>
> #include <fcntl.h>
> #include <net/if.h>
> #include <net/if_arp.h>
> #include <netinet/in.h>
> #include <pthread.h>
> #include <sched.h>
> #include <signal.h>
> #include <stdarg.h>
> #include <stdbool.h>
> #include <stdint.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <sys/ioctl.h>
> #include <sys/mount.h>
> #include <sys/prctl.h>
> #include <sys/resource.h>
> #include <sys/socket.h>
> #include <sys/stat.h>
> #include <sys/syscall.h>
> #include <sys/time.h>
> #include <sys/types.h>
> #include <sys/uio.h>
> #include <sys/wait.h>
> #include <time.h>
> #include <unistd.h>
>
> #include <linux/capability.h>
> #include <linux/futex.h>
> #include <linux/genetlink.h>
> #include <linux/if_addr.h>
> #include <linux/if_ether.h>
> #include <linux/if_link.h>
> #include <linux/if_tun.h>
> #include <linux/in6.h>
> #include <linux/ip.h>
> #include <linux/neighbour.h>
> #include <linux/net.h>
> #include <linux/netlink.h>
> #include <linux/rtnetlink.h>
> #include <linux/tcp.h>
> #include <linux/veth.h>
>
> static void sleep_ms(uint64_t ms)
> {
> usleep(ms * 1000);
> }
>
> static uint64_t current_time_ms(void)
> {
> struct timespec ts;
> if (clock_gettime(CLOCK_MONOTONIC, &ts))
> exit(1);
> return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
> }
>
> static void use_temporary_dir(void)
> {
> char tmpdir_template[] = "./syzkaller.XXXXXX";
> char* tmpdir = mkdtemp(tmpdir_template);
> if (!tmpdir)
> exit(1);
> if (chmod(tmpdir, 0777))
> exit(1);
> if (chdir(tmpdir))
> exit(1);
> }
>
> static void thread_start(void* (*fn)(void*), void* arg)
> {
> pthread_t th;
> pthread_attr_t attr;
> pthread_attr_init(&attr);
> pthread_attr_setstacksize(&attr, 128 << 10);
> int i = 0;
> for (; i < 100; i++) {
> if (pthread_create(&th, &attr, fn, arg) == 0) {
> pthread_attr_destroy(&attr);
> return;
> }
> if (errno == EAGAIN) {
> usleep(50);
> continue;
> }
> break;
> }
> exit(1);
> }
>
> typedef struct {
> int state;
> } event_t;
>
> static void event_init(event_t* ev)
> {
> ev->state = 0;
> }
>
> static void event_reset(event_t* ev)
> {
> ev->state = 0;
> }
>
> static void event_set(event_t* ev)
> {
> if (ev->state)
> exit(1);
> __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
> syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000);
> }
>
> static void event_wait(event_t* ev)
> {
> while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
> syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
> }
>
> static int event_isset(event_t* ev)
> {
> return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE);
> }
>
> static int event_timedwait(event_t* ev, uint64_t timeout)
> {
> uint64_t start = current_time_ms();
> uint64_t now = start;
> for (;;) {
> uint64_t remain = timeout - (now - start);
> struct timespec ts;
> ts.tv_sec = remain / 1000;
> ts.tv_nsec = (remain % 1000) * 1000 * 1000;
> syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts);
> if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
> return 1;
> now = current_time_ms();
> if (now - start > timeout)
> return 0;
> }
> }
>
> #define IFLA_IPVLAN_FLAGS 2
> #define IPVLAN_MODE_L3S 2
> #undef IPVLAN_F_VEPA
> #define IPVLAN_F_VEPA 2
>
> #define TUN_IFACE "syz_tun"
> #define LOCAL_MAC 0xaaaaaaaaaaaa
> #define REMOTE_MAC 0xaaaaaaaaaabb
> #define LOCAL_IPV4 "172.20.20.170"
> #define REMOTE_IPV4 "172.20.20.187"
> #define LOCAL_IPV6 "fe80::aa"
> #define REMOTE_IPV6 "fe80::bb"
>
> #define IFF_NAPI 0x0010
>
> #define DEVLINK_FAMILY_NAME "devlink"
>
> #define DEVLINK_CMD_PORT_GET 5
> #define DEVLINK_ATTR_BUS_NAME 1
> #define DEVLINK_ATTR_DEV_NAME 2
> #define DEVLINK_ATTR_NETDEV_NAME 7
>
> #define DEV_IPV4 "172.20.20.%d"
> #define DEV_IPV6 "fe80::%02x"
> #define DEV_MAC 0x00aaaaaaaaaa
>
> #define WG_GENL_NAME "wireguard"
> enum wg_cmd {
> WG_CMD_GET_DEVICE,
> WG_CMD_SET_DEVICE,
> };
> enum wgdevice_attribute {
> WGDEVICE_A_UNSPEC,
> WGDEVICE_A_IFINDEX,
> WGDEVICE_A_IFNAME,
> WGDEVICE_A_PRIVATE_KEY,
> WGDEVICE_A_PUBLIC_KEY,
> WGDEVICE_A_FLAGS,
> WGDEVICE_A_LISTEN_PORT,
> WGDEVICE_A_FWMARK,
> WGDEVICE_A_PEERS,
> };
> enum wgpeer_attribute {
> WGPEER_A_UNSPEC,
> WGPEER_A_PUBLIC_KEY,
> WGPEER_A_PRESHARED_KEY,
> WGPEER_A_FLAGS,
> WGPEER_A_ENDPOINT,
> WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
> WGPEER_A_LAST_HANDSHAKE_TIME,
> WGPEER_A_RX_BYTES,
> WGPEER_A_TX_BYTES,
> WGPEER_A_ALLOWEDIPS,
> WGPEER_A_PROTOCOL_VERSION,
> };
> enum wgallowedip_attribute {
> WGALLOWEDIP_A_UNSPEC,
> WGALLOWEDIP_A_FAMILY,
> WGALLOWEDIP_A_IPADDR,
> WGALLOWEDIP_A_CIDR_MASK,
> };
>
> #define MAX_FDS 30
>
> #define XT_TABLE_SIZE 1536
> #define XT_MAX_ENTRIES 10
>
> struct xt_counters {
> uint64_t pcnt, bcnt;
> };
>
> struct ipt_getinfo {
> char name[32];
> unsigned int valid_hooks;
> unsigned int hook_entry[5];
> unsigned int underflow[5];
> unsigned int num_entries;
> unsigned int size;
> };
>
> struct ipt_get_entries {
> char name[32];
> unsigned int size;
> uint64_t entrytable[XT_TABLE_SIZE / sizeof(uint64_t)];
> };
>
> struct ipt_replace {
> char name[32];
> unsigned int valid_hooks;
> unsigned int num_entries;
> unsigned int size;
> unsigned int hook_entry[5];
> unsigned int underflow[5];
> unsigned int num_counters;
> struct xt_counters* counters;
> uint64_t entrytable[XT_TABLE_SIZE / sizeof(uint64_t)];
> };
>
> struct ipt_table_desc {
> const char* name;
> struct ipt_getinfo info;
> struct ipt_replace replace;
> };
>
> #define IPT_BASE_CTL 64
> #define IPT_SO_SET_REPLACE (IPT_BASE_CTL)
> #define IPT_SO_GET_INFO (IPT_BASE_CTL)
> #define IPT_SO_GET_ENTRIES (IPT_BASE_CTL + 1)
>
> struct arpt_getinfo {
> char name[32];
> unsigned int valid_hooks;
> unsigned int hook_entry[3];
> unsigned int underflow[3];
> unsigned int num_entries;
> unsigned int size;
> };
>
> struct arpt_get_entries {
> char name[32];
> unsigned int size;
> uint64_t entrytable[XT_TABLE_SIZE / sizeof(uint64_t)];
> };
>
> struct arpt_replace {
> char name[32];
> unsigned int valid_hooks;
> unsigned int num_entries;
> unsigned int size;
> unsigned int hook_entry[3];
> unsigned int underflow[3];
> unsigned int num_counters;
> struct xt_counters* counters;
> uint64_t entrytable[XT_TABLE_SIZE / sizeof(uint64_t)];
> };
>
> #define ARPT_BASE_CTL 96
> #define ARPT_SO_SET_REPLACE (ARPT_BASE_CTL)
> #define ARPT_SO_GET_INFO (ARPT_BASE_CTL)
> #define ARPT_SO_GET_ENTRIES (ARPT_BASE_CTL + 1)
>
> static void loop();
>
> static int wait_for_loop(int pid)
> {
> if (pid < 0)
> exit(1);
> int status = 0;
> while (waitpid(-1, &status, __WALL) != pid) {
> }
> return WEXITSTATUS(status);
> }
>
> static int do_sandbox_none(void)
> {
> if (unshare(CLONE_NEWPID)) {
> }
> int pid = fork();
> if (pid != 0)
> return wait_for_loop(pid);
>
> if (unshare(CLONE_NEWNET)) {
> }
> loop();
> exit(1);
> }
>
> #define FS_IOC_SETFLAGS _IOW('f', 2, long)
> static void remove_dir(const char* dir)
> {
> int iter = 0;
> DIR* dp = 0;
> retry:
> while (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) {
> }
> dp = opendir(dir);
> if (dp == NULL) {
> if (errno == EMFILE) {
> exit(1);
> }
> exit(1);
> }
> struct dirent* ep = 0;
> while ((ep = readdir(dp))) {
> if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
> continue;
> char filename[FILENAME_MAX];
> snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
> while (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) {
> }
> struct stat st;
> if (lstat(filename, &st))
> exit(1);
> if (S_ISDIR(st.st_mode)) {
> remove_dir(filename);
> continue;
> }
> int i;
> for (i = 0;; i++) {
> if (unlink(filename) == 0)
> break;
> if (errno == EPERM) {
> int fd = open(filename, O_RDONLY);
> if (fd != -1) {
> long flags = 0;
> if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
> }
> close(fd);
> continue;
> }
> }
> if (errno == EROFS) {
> break;
> }
> if (errno != EBUSY || i > 100)
> exit(1);
> if (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW))
> exit(1);
> }
> }
> closedir(dp);
> for (int i = 0;; i++) {
> if (rmdir(dir) == 0)
> break;
> if (i < 100) {
> if (errno == EPERM) {
> int fd = open(dir, O_RDONLY);
> if (fd != -1) {
> long flags = 0;
> if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) {
> }
> close(fd);
> continue;
> }
> }
> if (errno == EROFS) {
> break;
> }
> if (errno == EBUSY) {
> if (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW))
> exit(1);
> continue;
> }
> if (errno == ENOTEMPTY) {
> if (iter < 100) {
> iter++;
> goto retry;
> }
> }
> }
> exit(1);
> }
> }
>
> static void kill_and_wait(int pid, int* status)
> {
> kill(-pid, SIGKILL);
> kill(pid, SIGKILL);
> for (int i = 0; i < 100; i++) {
> if (waitpid(-1, status, WNOHANG | __WALL) == pid)
> return;
> usleep(1000);
> }
> DIR* dir = opendir("/sys/fs/fuse/connections");
> if (dir) {
> for (;;) {
> struct dirent* ent = readdir(dir);
> if (!ent)
> break;
> if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
> continue;
> char abort[300];
> snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
> ent->d_name);
> int fd = open(abort, O_WRONLY);
> if (fd == -1) {
> continue;
> }
> if (write(fd, abort, 1) < 0) {
> }
> close(fd);
> }
> closedir(dir);
> } else {
> }
> while (waitpid(-1, status, __WALL) != pid) {
> }
> }
>
> static void close_fds()
> {
> for (int fd = 3; fd < MAX_FDS; fd++)
> close(fd);
> }
>
> struct thread_t {
> int created, call;
> event_t ready, done;
> };
>
> static struct thread_t threads[16];
> static void execute_call(int call);
> static int running;
>
> static void* thr(void* arg)
> {
> struct thread_t* th = (struct thread_t*)arg;
> for (;;) {
> event_wait(&th->ready);
> event_reset(&th->ready);
> execute_call(th->call);
> __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
> event_set(&th->done);
> }
> return 0;
> }
>
> static void execute_one(void)
> {
> int i, call, thread;
> for (call = 0; call < 10; call++) {
> for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0]));
> thread++) {
> struct thread_t* th = &threads[thread];
> if (!th->created) {
> th->created = 1;
> event_init(&th->ready);
> event_init(&th->done);
> event_set(&th->done);
> thread_start(thr, th);
> }
> if (!event_isset(&th->done))
> continue;
> event_reset(&th->done);
> th->call = call;
> __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
> event_set(&th->ready);
> event_timedwait(&th->done, 50);
> break;
> }
> }
> for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
> sleep_ms(1);
> close_fds();
> }
>
> static void execute_one(void);
>
> #define WAIT_FLAGS __WALL
>
> static void loop(void)
> {
> int iter = 0;
> for (;; iter++) {
> char cwdbuf[32];
> sprintf(cwdbuf, "./%d", iter);
> if (mkdir(cwdbuf, 0777))
> exit(1);
> int pid = fork();
> if (pid < 0)
> exit(1);
> if (pid == 0) {
> if (chdir(cwdbuf))
> exit(1);
> execute_one();
> exit(0);
> }
> int status = 0;
> uint64_t start = current_time_ms();
> for (;;) {
> if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) {
> break;
> }
> sleep_ms(1);
> if (current_time_ms() - start < 5000)
> continue;
> kill_and_wait(pid, &status);
> break;
> }
> remove_dir(cwdbuf);
> }
> }
>
> uint64_t r[5] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
> 0xffffffffffffffff, 0x0};
>
> void execute_call(int call)
> {
> intptr_t res = 0;
> switch (call) {
> case 0:
> memcpy((void*)0x20000080, "./bus\000", 6);
> res = syscall(__NR_open, 0x20000080ul, 0x14d842ul, 0ul);
> if (res != -1)
> r[0] = res;
> break;
> case 1:
> memcpy((void*)0x20000000, "/proc/self/exe\000", 15);
> res = syscall(__NR_openat, 0xffffff9c, 0x20000000ul, 0ul, 0ul);
> if (res != -1)
> r[1] = res;
> break;
> case 2:
> memcpy((void*)0x20002000, "./bus\000", 6);
> res = syscall(__NR_open, 0x20002000ul, 0x143042ul, 0ul);
> if (res != -1)
> r[2] = res;
> break;
> case 3:
> syscall(__NR_ftruncate, r[2], 0x2008002ul);
> break;
> case 4:
> memcpy((void*)0x20000400, "./bus\000", 6);
> res = syscall(__NR_open, 0x20000400ul, 0x14103eul, 0ul);
> if (res != -1)
> r[3] = res;
> break;
> case 5:
> syscall(__NR_mmap, 0x20000000ul, 0x600000ul, 0x7ffffeul, 0x11ul, r[3], 0ul);
> break;
> case 6:
> syscall(__NR_sendfile, r[0], r[1], 0ul, 0x80000005ul);
> break;
> case 7:
> res = syscall(__NR_gettid);
> if (res != -1)
> r[4] = res;
> break;
> case 8:
> *(uint64_t*)0x20c22000 = 0x2034afa4;
> *(uint64_t*)0x20c22008 = 0x1f80;
> *(uint64_t*)0x20c22fa0 = 0x20000080;
> *(uint64_t*)0x20c22fa8 = 0x2034afa5;
> syscall(__NR_process_vm_writev, r[4], 0x20c22000ul, 1ul, 0x20c22fa0ul, 1ul,
> 0ul);
> break;
> case 9:
> syscall(__NR_sendfile, r[0], r[1], 0ul, 0x80000005ul);
> break;
> }
> }
> int main(void)
> {
> syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
> syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
> syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
>
> use_temporary_dir();
> do_sandbox_none();
>
> return 0;
> }
>
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