On Wed, Sep 15, 2021 at 12:34 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > On Wed, Sep 15, 2021 at 09:49:49AM +0800, Hao Sun wrote: > > console output: https://paste.ubuntu.com/p/5qHqPXWmCQ/ > > kernel config: https://paste.ubuntu.com/p/VsVbFh9ZpQ/ > > C reproducer: https://paste.ubuntu.com/p/yrYsn4zpcn/ > > Syzlang reproducer: https://paste.ubuntu.com/p/bCWyNyHncJ/ > > > > Just tried the C reproducer on the latest Linux kernel (6880fa6c5660 > > Linux 5.15-rc1). > > The reproducer still crashed the kernel but with a different backtrace. > > Well, that trace looks very much like an issue in the MM truncate code. > Adding the linux-mm list. The BUG is triggered if it tries to invalidate across pages. But it hardcoded PAGE_SIZE. The offset passed in by truncate_cleanup_page() is 0, but the length might be > PAGE_SIZE if it is a compound page. It might be caused by READ_ONLY_THP_FOR_FS. Could you please try the below debug patch to dump page details? I saw your kernel config has DEBUG_VM enabled. diff --git a/fs/buffer.c b/fs/buffer.c index ab7573d72dd7..ed7256112c2b 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1507,7 +1507,8 @@ void block_invalidatepage(struct page *page, unsigned int offset, /* * Check for overflow */ - BUG_ON(stop > PAGE_SIZE || stop < length); + VM_BUG_ON_PAGE((stop > PAGE_SIZE), page); + VM_BUG_ON_PAGE((stop < length), page); head = page_buffers(page); bh = head; If my speculation is correct, I think the below patch should be able to fix this issue. diff --git a/fs/buffer.c b/fs/buffer.c index ab7573d72dd7..18428cee59af 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1507,7 +1507,7 @@ void block_invalidatepage(struct page *page, unsigned int offset, /* * Check for overflow */ - BUG_ON(stop > PAGE_SIZE || stop < length); + BUG_ON(stop > thp_size(page) || stop < length); head = page_buffers(page); bh = head; > > > > > IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready > > IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready > > Bluetooth: hci0: command 0x0409 tx timeout > > ------------[ cut here ]------------ > > kernel BUG at fs/buffer.c:1510! > > invalid opcode: 0000 [#1] PREEMPT SMP > > CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.14.0+ #15 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > > rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 > > Workqueue: events delayed_fput > > RIP: 0010:block_invalidatepage+0x27f/0x2a0 -origin/fs/buffer.c:1510 > > Code: ff ff e8 b4 07 d7 ff b9 02 00 00 00 be 02 00 00 00 4c 89 ff 48 > > c7 c2 40 4e 25 84 e8 2b c2 c4 02 e9 c9 fe ff ff e8 91 07 d7 ff <0f> 0b > > e8 8a 07 d7 ff 0f 0b e8 83 07 d7 ff 48 8d 5d ff e9 57 ff ff > > RSP: 0018:ffffc9000065bb60 EFLAGS: 00010293 > > RAX: 0000000000000000 RBX: ffffea0000670000 RCX: 0000000000000000 > > RDX: ffff8880097fa240 RSI: ffffffff81608a9f RDI: ffffea0000670000 > > RBP: ffffea0000670000 R08: 0000000000000001 R09: 0000000000000000 > > R10: ffffc9000065b9f8 R11: 0000000000000003 R12: ffffffff81608820 > > R13: ffffc9000065bc68 R14: 0000000000000000 R15: ffffc9000065bbf0 > > FS: 0000000000000000(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f4aef93fb08 CR3: 0000000108cf2000 CR4: 0000000000750ef0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > PKRU: 55555554 > > Call Trace: > > do_invalidatepage -origin/mm/truncate.c:157 [inline] > > truncate_cleanup_page+0x15c/0x280 -origin/mm/truncate.c:176 > > truncate_inode_pages_range+0x169/0xc30 -origin/mm/truncate.c:325 > > kill_bdev.isra.29+0x28/0x30 > > blkdev_flush_mapping+0x4c/0x130 -origin/block/bdev.c:658 > > blkdev_put_whole+0x54/0x60 -origin/block/bdev.c:689 > > blkdev_put+0x6f/0x210 -origin/block/bdev.c:953 > > blkdev_close+0x25/0x30 -origin/block/fops.c:459 > > __fput+0xdf/0x380 -origin/fs/file_table.c:280 > > delayed_fput+0x25/0x40 -origin/fs/file_table.c:308 > > process_one_work+0x359/0x850 -origin/kernel/workqueue.c:2297 > > worker_thread+0x41/0x4d0 -origin/kernel/workqueue.c:2444 > > kthread+0x178/0x1b0 -origin/kernel/kthread.c:319 > > ret_from_fork+0x1f/0x30 -origin/arch/x86/entry/entry_64.S:295 > > Modules linked in: > > Dumping ftrace buffer: > > (ftrace buffer empty) > > ---[ end trace 9dbb8f58f2109f10 ]--- > > RIP: 0010:block_invalidatepage+0x27f/0x2a0 -origin/fs/buffer.c:1510 > > Code: ff ff e8 b4 07 d7 ff b9 02 00 00 00 be 02 00 00 00 4c 89 ff 48 > > c7 c2 40 4e 25 84 e8 2b c2 c4 02 e9 c9 fe ff ff e8 91 07 d7 ff <0f> 0b > > e8 8a 07 d7 ff 0f 0b e8 83 07 d7 ff 48 8d 5d ff e9 57 ff ff > > RSP: 0018:ffffc9000065bb60 EFLAGS: 00010293 > > RAX: 0000000000000000 RBX: ffffea0000670000 RCX: 0000000000000000 > > RDX: ffff8880097fa240 RSI: ffffffff81608a9f RDI: ffffea0000670000 > > RBP: ffffea0000670000 R08: 0000000000000001 R09: 0000000000000000 > > R10: ffffc9000065b9f8 R11: 0000000000000003 R12: ffffffff81608820 > > R13: ffffc9000065bc68 R14: 0000000000000000 R15: ffffc9000065bbf0 > > FS: 0000000000000000(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007ff98674f000 CR3: 0000000106b2e000 CR4: 0000000000750ef0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > PKRU: 55555554 > ---end quoted text---
