Sorry, please ignore my reply... (If there no truncate and commit race...)
On 2019/2/25 17:25, Gao Xiang wrote: > Hi Chao, > > On 2019/2/25 17:11, Chao Yu wrote: >> Thread A Thread B >> - __fput >> - f2fs_release_file >> - drop_inmem_pages >> - mutex_lock(&fi->inmem_lock) >> - __revoke_inmem_pages >> - lock_page(page) >> - open >> - f2fs_setattr >> - truncate_setsize >> - truncate_inode_pages_range >> - lock_page(page) >> - truncate_cleanup_page >> - f2fs_invalidate_page >> - drop_inmem_page >> - mutex_lock(&fi->inmem_lock); >> >> We may encounter above ABBA deadlock as reported by Kyungtae Kim: >> >> I'm reporting a bug in linux-4.17.19: "INFO: task hung in >> drop_inmem_page" (no reproducer) >> >> I think this might be somehow related to the following: >> https://groups.google.com/forum/#!searchin/syzkaller-bugs/INFO$3A$20task$20hung$20in$20%7Csort:date/syzkaller-bugs/c6soBTrdaIo/AjAzPeIzCgAJ >> >> ========================================= >> INFO: task syz-executor7:10822 blocked for more than 120 seconds. >> Not tainted 4.17.19 #1 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> syz-executor7 D27024 10822 6346 0x00000004 >> Call Trace: >> context_switch kernel/sched/core.c:2867 [inline] >> __schedule+0x721/0x1e60 kernel/sched/core.c:3515 >> schedule+0x88/0x1c0 kernel/sched/core.c:3559 >> schedule_preempt_disabled+0x18/0x30 kernel/sched/core.c:3617 >> __mutex_lock_common kernel/locking/mutex.c:833 [inline] >> __mutex_lock+0x5bd/0x1410 kernel/locking/mutex.c:893 >> mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:908 >> drop_inmem_page+0xcb/0x810 fs/f2fs/segment.c:327 >> f2fs_invalidate_page+0x337/0x5e0 fs/f2fs/data.c:2401 >> do_invalidatepage mm/truncate.c:165 [inline] >> truncate_cleanup_page+0x261/0x330 mm/truncate.c:187 >> truncate_inode_pages_range+0x552/0x1610 mm/truncate.c:367 >> truncate_inode_pages mm/truncate.c:478 [inline] >> truncate_pagecache+0x6d/0x90 mm/truncate.c:801 >> truncate_setsize+0x81/0xa0 mm/truncate.c:826 >> f2fs_setattr+0x44f/0x1270 fs/f2fs/file.c:781 >> notify_change+0xa62/0xe80 fs/attr.c:313 >> do_truncate+0x12e/0x1e0 fs/open.c:63 >> do_last fs/namei.c:2955 [inline] >> path_openat+0x2042/0x29f0 fs/namei.c:3505 >> do_filp_open+0x1bd/0x2c0 fs/namei.c:3540 >> do_sys_open+0x35e/0x4e0 fs/open.c:1101 >> __do_sys_open fs/open.c:1119 [inline] >> __se_sys_open fs/open.c:1114 [inline] >> __x64_sys_open+0x89/0xc0 fs/open.c:1114 >> do_syscall_64+0xc4/0x4e0 arch/x86/entry/common.c:287 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x4497b9 >> RSP: 002b:00007f734e459c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 >> RAX: ffffffffffffffda RBX: 00007f734e45a6cc RCX: 00000000004497b9 >> RDX: 0000000000000104 RSI: 00000000000a8280 RDI: 0000000020000080 >> RBP: 000000000071bea0 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff >> R13: 0000000000007230 R14: 00000000006f02d0 R15: 00007f734e45a700 >> INFO: task syz-executor7:10858 blocked for more than 120 seconds. >> Not tainted 4.17.19 #1 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> syz-executor7 D28880 10858 6346 0x00000004 >> Call Trace: >> context_switch kernel/sched/core.c:2867 [inline] >> __schedule+0x721/0x1e60 kernel/sched/core.c:3515 >> schedule+0x88/0x1c0 kernel/sched/core.c:3559 >> __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:565 [inline] >> rwsem_down_write_failed+0x5e6/0xc90 kernel/locking/rwsem-xadd.c:594 >> call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 >> __down_write arch/x86/include/asm/rwsem.h:142 [inline] >> down_write+0x58/0xa0 kernel/locking/rwsem.c:72 >> inode_lock include/linux/fs.h:713 [inline] >> do_truncate+0x120/0x1e0 fs/open.c:61 >> do_last fs/namei.c:2955 [inline] >> path_openat+0x2042/0x29f0 fs/namei.c:3505 >> do_filp_open+0x1bd/0x2c0 fs/namei.c:3540 >> do_sys_open+0x35e/0x4e0 fs/open.c:1101 >> __do_sys_open fs/open.c:1119 [inline] >> __se_sys_open fs/open.c:1114 [inline] >> __x64_sys_open+0x89/0xc0 fs/open.c:1114 >> do_syscall_64+0xc4/0x4e0 arch/x86/entry/common.c:287 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x4497b9 >> RSP: 002b:00007f734e3b4c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 >> RAX: ffffffffffffffda RBX: 00007f734e3b56cc RCX: 00000000004497b9 >> RDX: 0000000000000104 RSI: 00000000000a8280 RDI: 0000000020000080 >> RBP: 000000000071c238 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff >> R13: 0000000000007230 R14: 00000000006f02d0 R15: 00007f734e3b5700 >> INFO: task syz-executor5:10829 blocked for more than 120 seconds. >> Not tainted 4.17.19 #1 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> syz-executor5 D28760 10829 6308 0x80000002 >> Call Trace: >> context_switch kernel/sched/core.c:2867 [inline] >> __schedule+0x721/0x1e60 kernel/sched/core.c:3515 >> schedule+0x88/0x1c0 kernel/sched/core.c:3559 >> io_schedule+0x21/0x80 kernel/sched/core.c:5179 >> wait_on_page_bit_common mm/filemap.c:1100 [inline] >> __lock_page+0x2b5/0x390 mm/filemap.c:1273 >> lock_page include/linux/pagemap.h:483 [inline] >> __revoke_inmem_pages+0xb35/0x11c0 fs/f2fs/segment.c:231 >> drop_inmem_pages+0xa3/0x3e0 fs/f2fs/segment.c:306 >> f2fs_release_file+0x2c7/0x330 fs/f2fs/file.c:1556 >> __fput+0x2c7/0x780 fs/file_table.c:209 >> ____fput+0x1a/0x20 fs/file_table.c:243 >> task_work_run+0x151/0x1d0 kernel/task_work.c:113 >> exit_task_work include/linux/task_work.h:22 [inline] >> do_exit+0x8ba/0x30a0 kernel/exit.c:865 >> do_group_exit+0x13b/0x3a0 kernel/exit.c:968 >> get_signal+0x6bb/0x1650 kernel/signal.c:2482 >> do_signal+0x84/0x1b70 arch/x86/kernel/signal.c:810 >> exit_to_usermode_loop+0x155/0x190 arch/x86/entry/common.c:162 >> prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] >> syscall_return_slowpath arch/x86/entry/common.c:265 [inline] >> do_syscall_64+0x445/0x4e0 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x4497b9 >> RSP: 002b:00007f1c68e74ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca >> RAX: fffffffffffffe00 RBX: 000000000071bf80 RCX: 00000000004497b9 >> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000071bf80 >> RBP: 000000000071bf80 R08: 0000000000000000 R09: 000000000071bf58 >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >> R13: 0000000000000000 R14: 00007f1c68e759c0 R15: 00007f1c68e75700 >> >> This patch tries to use trylock_page to mitigate such deadlock condition >> for fix. >> >> Signed-off-by: Chao Yu <[email protected]> >> --- >> v2: >> - fix wrong mutex_unlock position. >> fs/f2fs/segment.c | 43 +++++++++++++++++++++++++++++++------------ >> 1 file changed, 31 insertions(+), 12 deletions(-) >> >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index fdd8cd21522f..ca786913b2c6 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -215,7 +215,8 @@ void f2fs_register_inmem_page(struct inode *inode, >> struct page *page) >> } >> >> static int __revoke_inmem_pages(struct inode *inode, >> - struct list_head *head, bool drop, bool recover) >> + struct list_head *head, bool drop, bool recover, >> + bool trylock) >> { >> struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> struct inmem_pages *cur, *tmp; >> @@ -227,7 +228,16 @@ static int __revoke_inmem_pages(struct inode *inode, >> if (drop) >> trace_f2fs_commit_inmem_page(page, INMEM_DROP); >> >> - lock_page(page); >> + if (trylock) { >> + /* >> + * to avoid deadlock in between page lock and >> + * inmem_lock. >> + */ >> + if (!trylock_page(page)) >> + continue; > > Will it cause memleak? since revoke_list is a temporary local linked list... > Is there a better way than just simplily skip it? > > Thanks, > Gao Xiang > >> + } else { >> + lock_page(page); >> + } >> >> f2fs_wait_on_page_writeback(page, DATA, true, true); >> >> @@ -318,13 +328,19 @@ void f2fs_drop_inmem_pages(struct inode *inode) >> struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> struct f2fs_inode_info *fi = F2FS_I(inode); >> >> - mutex_lock(&fi->inmem_lock); >> - __revoke_inmem_pages(inode, &fi->inmem_pages, true, false); >> - spin_lock(&sbi->inode_lock[ATOMIC_FILE]); >> - if (!list_empty(&fi->inmem_ilist)) >> - list_del_init(&fi->inmem_ilist); >> - spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); >> - mutex_unlock(&fi->inmem_lock); >> + while (!list_empty(&fi->inmem_pages)) { >> + mutex_lock(&fi->inmem_lock); >> + __revoke_inmem_pages(inode, &fi->inmem_pages, >> + true, false, true); >> + >> + if (list_empty(&fi->inmem_pages)) { >> + spin_lock(&sbi->inode_lock[ATOMIC_FILE]); >> + if (!list_empty(&fi->inmem_ilist)) >> + list_del_init(&fi->inmem_ilist); >> + spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); >> + } >> + mutex_unlock(&fi->inmem_lock); >> + } >> >> clear_inode_flag(inode, FI_ATOMIC_FILE); >> fi->i_gc_failures[GC_FAILURE_ATOMIC] = 0; >> @@ -429,12 +445,15 @@ static int __f2fs_commit_inmem_pages(struct inode >> *inode) >> * recovery or rewrite & commit last transaction. For other >> * error number, revoking was done by filesystem itself. >> */ >> - err = __revoke_inmem_pages(inode, &revoke_list, false, true); >> + err = __revoke_inmem_pages(inode, &revoke_list, >> + false, true, false); >> >> /* drop all uncommitted pages */ >> - __revoke_inmem_pages(inode, &fi->inmem_pages, true, false); >> + __revoke_inmem_pages(inode, &fi->inmem_pages, >> + true, false, false); >> } else { >> - __revoke_inmem_pages(inode, &revoke_list, false, false); >> + __revoke_inmem_pages(inode, &revoke_list, >> + false, false, false); >> } >> >> return err; >> > > > _______________________________________________ > Linux-f2fs-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel >
