Messages in this thread | | | Date | Mon, 19 Jun 2023 22:15:10 +0800 | Subject | Re: [f2fs-dev] [PATCH v2] f2fs: fix to avoid mmap vs set_compress_option case | From | Chao Yu <> |
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On 2023/6/16 14:03, Eric Biggers wrote: > Hi Chao,
Eric,
Thanks for the report, let me check this.
Thanks,
> > On Mon, May 29, 2023 at 06:47:09PM +0800, Chao Yu wrote: >> Compression option in inode should not be changed after they have >> been used, however, it may happen in below race case: >> >> Thread A Thread B >> - f2fs_ioc_set_compress_option >> - check f2fs_is_mmap_file() >> - check get_dirty_pages() >> - check F2FS_HAS_BLOCKS() >> - f2fs_file_mmap >> - set_inode_flag(FI_MMAP_FILE) >> - fault >> - do_page_mkwrite >> - f2fs_vm_page_mkwrite >> - f2fs_get_block_locked >> - fault_dirty_shared_page >> - set_page_dirty >> - update i_compress_algorithm >> - update i_log_cluster_size >> - update i_cluster_size >> >> Avoid such race condition by covering f2fs_file_mmap() w/ inode lock, >> meanwhile add mmap file check condition in f2fs_may_compress() as well. >> >> Fixes: e1e8debec656 ("f2fs: add F2FS_IOC_SET_COMPRESS_OPTION ioctl") >> Signed-off-by: Chao Yu <chao@kernel.org> > > This patch causes the following deadlock report: > > [ 9.622928] ====================================================== > [ 9.623484] WARNING: possible circular locking dependency detected > [ 9.624054] 6.4.0-rc1-00039-g18a87f3eaef5 #12 Tainted: G T > [ 9.624672] ------------------------------------------------------ > [ 9.625242] xfs_io/2440 is trying to acquire lock: > [ 9.625682] ffff888103a2c888 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: f2fs_file_mmap+0x53/0xc0 > [ 9.626523] > [ 9.626523] but task is already holding lock: > [ 9.627058] ffff888103d0e8c0 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x72/0x1c0 > [ 9.627797] > [ 9.627797] which lock already depends on the new lock. > [ 9.627797] > [ 9.628528] > [ 9.628528] the existing dependency chain (in reverse order) is: > [ 9.629210] > [ 9.629210] -> #1 (&mm->mmap_lock){++++}-{3:3}: > [ 9.629761] lock_acquire+0xcb/0x2d0 > [ 9.630147] __might_fault+0x6f/0xa0 > [ 9.630526] _copy_to_user+0x27/0x90 > [ 9.630915] fiemap_fill_next_extent+0xbe/0x130 > [ 9.631378] f2fs_fiemap+0x223/0x5c0 > [ 9.631757] do_vfs_ioctl+0x6d5/0x860 > [ 9.632150] __x64_sys_ioctl+0x4a/0xd0 > [ 9.632547] do_syscall_64+0x39/0x90 > [ 9.632935] entry_SYSCALL_64_after_hwframe+0x63/0xcd > [ 9.633444] > [ 9.633444] -> #0 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}: > [ 9.634104] check_prev_add+0x93/0xbd0 > [ 9.634500] __lock_acquire+0xc27/0x11e0 > [ 9.634918] lock_acquire+0xcb/0x2d0 > [ 9.635297] down_write+0x3d/0x100 > [ 9.635660] f2fs_file_mmap+0x53/0xc0 > [ 9.636053] mmap_region+0x20b/0x920 > [ 9.636433] do_mmap+0x345/0x570 > [ 9.636781] vm_mmap_pgoff+0xa1/0x1c0 > [ 9.637179] ksys_mmap_pgoff+0xa0/0xc0 > [ 9.637574] __x64_sys_mmap+0x32/0x60 > [ 9.637970] do_syscall_64+0x39/0x90 > [ 9.638348] entry_SYSCALL_64_after_hwframe+0x63/0xcd > [ 9.638864] > [ 9.638864] other info that might help us debug this: > [ 9.638864] > [ 9.639582] Possible unsafe locking scenario: > [ 9.639582] > [ 9.640128] CPU0 CPU1 > [ 9.640545] ---- ---- > [ 9.640971] lock(&mm->mmap_lock); > [ 9.641298] lock(&sb->s_type->i_mutex_key#11); > [ 9.641953] lock(&mm->mmap_lock); > [ 9.642500] lock(&sb->s_type->i_mutex_key#11); > [ 9.642930] > [ 9.642930] *** DEADLOCK *** > [ 9.642930] > [ 9.643469] 1 lock held by xfs_io/2440: > [ 9.643830] #0: ffff888103d0e8c0 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x72/0x1c0 > [ 9.644600] > [ 9.644600] stack backtrace: > [ 9.645012] CPU: 0 PID: 2440 Comm: xfs_io Tainted: G T 6.4.0-rc1-00039-g18a87f3eaef5 #12 > [ 9.645869] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Arch Linux 1.16.2-1-1 04/01/2014 > [ 9.646697] Call Trace: > [ 9.646933] <TASK> > [ 9.647137] dump_stack_lvl+0x4e/0x90 > [ 9.647483] dump_stack+0x14/0x20 > [ 9.647800] print_circular_bug+0x2eb/0x440 > [ 9.648188] check_noncircular+0x124/0x140 > [ 9.648568] check_prev_add+0x93/0xbd0 > [ 9.648923] ? add_chain_cache+0x10e/0x470 > [ 9.649304] __lock_acquire+0xc27/0x11e0 > [ 9.649670] lock_acquire+0xcb/0x2d0 > [ 9.650013] ? f2fs_file_mmap+0x53/0xc0 > [ 9.650372] down_write+0x3d/0x100 > [ 9.650696] ? f2fs_file_mmap+0x53/0xc0 > [ 9.651059] f2fs_file_mmap+0x53/0xc0 > [ 9.651402] mmap_region+0x20b/0x920 > [ 9.651739] do_mmap+0x345/0x570 > [ 9.652053] vm_mmap_pgoff+0xa1/0x1c0 > [ 9.652397] ksys_mmap_pgoff+0xa0/0xc0 > [ 9.652747] __x64_sys_mmap+0x32/0x60 > [ 9.653098] do_syscall_64+0x39/0x90 > [ 9.653432] entry_SYSCALL_64_after_hwframe+0x63/0xcd > [ 9.653904] RIP: 0033:0x7f1366f92b62 > [ 9.654237] Code: e4 e8 b2 4b 01 00 66 90 41 f7 c1 ff 0f 00 00 75 27 55 48 89 fd 53 89 cb 48 85 ff 74 3b 41 89 da 48 89 ef 4 > [ 9.655918] RSP: 002b:00007ffd5de38f08 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 > [ 9.656601] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f1366f92b62 > [ 9.657256] RDX: 0000000000000001 RSI: 0000000000020000 RDI: 0000000000000000 > [ 9.657909] RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000 > [ 9.658558] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 > [ 9.659215] R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000020000 > [ 9.659867] </TASK> >
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