From: Chao Yu yuchao0@huawei.com
[ Upstream commit 48432984d718c95cf13e26d487c2d1b697c3c01f ]
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/#%21searchin/syzkaller-bugs/INFO%243A%2420ta...
========================================= 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 yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 30779aaa9dba..1fa6f8185766 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -216,7 +216,8 @@ 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; @@ -228,7 +229,16 @@ 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; + } else { + lock_page(page); + }
f2fs_wait_on_page_writeback(page, DATA, true);
@@ -317,13 +327,19 @@ 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; @@ -427,12 +443,15 @@ 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;