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Chao Yu 48432984d7 f2fs: fix to avoid deadlock of atomic file operations
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 <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2019-03-12 18:59:19 -07:00
Documentation f2fs: fix to document inline_xattr_size option 2019-03-05 19:58:05 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
arch arch: restore generic-y += shmparam.h for some architectures 2019-01-06 18:16:11 -08:00
block for-4.21/block-20190102 2019-01-02 18:49:58 -08:00
certs kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
crypto Kconfig updates for v4.21 2018-12-29 13:03:29 -08:00
drivers chrome platform changes for v4.21 2019-01-06 11:40:06 -08:00
firmware kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
fs f2fs: fix to avoid deadlock of atomic file operations 2019-03-12 18:59:19 -07:00
include f2fs: correct spelling mistake 2019-03-12 18:59:17 -07:00
init jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
lib Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
mm Change mincore() to count "mapped" pages rather than "cached" pages 2019-01-06 13:43:02 -08:00
net jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
samples Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid 2019-01-05 17:53:40 -08:00
scripts kconfig: rename generated .*conf-cfg to *conf-cfg 2019-01-06 10:47:09 +09:00
security Merge branch 'mount.part1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-01-05 13:25:58 -08:00
sound Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
tools Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
.clang-format page cache: Convert find_get_pages_contig to XArray 2018-10-21 10:46:34 -04:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap A few early MIPS fixes for 4.21: 2019-01-05 12:48:25 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Add CREDITS entry for Shaohua Li 2019-01-04 14:27:09 -07:00
Kbuild kbuild: use assignment instead of define ... endef for filechk_* rules 2019-01-06 10:22:35 +09:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS chrome platform changes for v4.21 2019-01-06 11:40:06 -08:00
Makefile Linux 5.0-rc1 2019-01-06 17:08:20 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.