linux

mainlining shenanigans

Go to file

Tetsuo Handa bb422a738f mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed. Syzbot caught an oops at unregister_shrinker() because combination of commit `1d3d4437ea` ("vmscan: per-node deferred work") and fault injection made register_shrinker() fail and the caller of register_shrinker() did not check for failure. ---------- [ 554.881422] FAULT_INJECTION: forcing a failure. [ 554.881422] name failslab, interval 1, probability 0, space 0, times 0 [ 554.881438] CPU: 1 PID: 13231 Comm: syz-executor1 Not tainted 4.14.0-rc8+ #82 [ 554.881443] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 554.881445] Call Trace: [ 554.881459] dump_stack+0x194/0x257 [ 554.881474] ? arch_local_irq_restore+0x53/0x53 [ 554.881486] ? find_held_lock+0x35/0x1d0 [ 554.881507] should_fail+0x8c0/0xa40 [ 554.881522] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 554.881537] ? check_noncircular+0x20/0x20 [ 554.881546] ? find_next_zero_bit+0x2c/0x40 [ 554.881560] ? ida_get_new_above+0x421/0x9d0 [ 554.881577] ? find_held_lock+0x35/0x1d0 [ 554.881594] ? __lock_is_held+0xb6/0x140 [ 554.881628] ? check_same_owner+0x320/0x320 [ 554.881634] ? lock_downgrade+0x990/0x990 [ 554.881649] ? find_held_lock+0x35/0x1d0 [ 554.881672] should_failslab+0xec/0x120 [ 554.881684] __kmalloc+0x63/0x760 [ 554.881692] ? lock_downgrade+0x990/0x990 [ 554.881712] ? register_shrinker+0x10e/0x2d0 [ 554.881721] ? trace_event_raw_event_module_request+0x320/0x320 [ 554.881737] register_shrinker+0x10e/0x2d0 [ 554.881747] ? prepare_kswapd_sleep+0x1f0/0x1f0 [ 554.881755] ? _down_write_nest_lock+0x120/0x120 [ 554.881765] ? memcpy+0x45/0x50 [ 554.881785] sget_userns+0xbcd/0xe20 (...snipped...) [ 554.898693] kasan: CONFIG_KASAN_INLINE enabled [ 554.898724] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 554.898732] general protection fault: 0000 [#1] SMP KASAN [ 554.898737] Dumping ftrace buffer: [ 554.898741] (ftrace buffer empty) [ 554.898743] Modules linked in: [ 554.898752] CPU: 1 PID: 13231 Comm: syz-executor1 Not tainted 4.14.0-rc8+ #82 [ 554.898755] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 554.898760] task: ffff8801d1dbe5c0 task.stack: ffff8801c9e38000 [ 554.898772] RIP: 0010:__list_del_entry_valid+0x7e/0x150 [ 554.898775] RSP: 0018:ffff8801c9e3f108 EFLAGS: 00010246 [ 554.898780] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 554.898784] RDX: 0000000000000000 RSI: ffff8801c53c6f98 RDI: ffff8801c53c6fa0 [ 554.898788] RBP: ffff8801c9e3f120 R08: 1ffff100393c7d55 R09: 0000000000000004 [ 554.898791] R10: ffff8801c9e3ef70 R11: 0000000000000000 R12: 0000000000000000 [ 554.898795] R13: dffffc0000000000 R14: 1ffff100393c7e45 R15: ffff8801c53c6f98 [ 554.898800] FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 554.898804] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 554.898807] CR2: 00000000dbc23000 CR3: 00000001c7269000 CR4: 00000000001406e0 [ 554.898813] DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 [ 554.898816] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 [ 554.898818] Call Trace: [ 554.898828] unregister_shrinker+0x79/0x300 [ 554.898837] ? perf_trace_mm_vmscan_writepage+0x750/0x750 [ 554.898844] ? down_write+0x87/0x120 [ 554.898851] ? deactivate_super+0x139/0x1b0 [ 554.898857] ? down_read+0x150/0x150 [ 554.898864] ? check_same_owner+0x320/0x320 [ 554.898875] deactivate_locked_super+0x64/0xd0 [ 554.898883] deactivate_super+0x141/0x1b0 ---------- Since allowing register_shrinker() callers to call unregister_shrinker() when register_shrinker() failed can simplify error recovery path, this patch makes unregister_shrinker() no-op when register_shrinker() failed. Also, reset shrinker->nr_deferred in case unregister_shrinker() was by error called twice. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Aliaksei Karaliou <akaraliou.dev@gmail.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: Glauber Costa <glauber@scylladb.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>		2017-12-18 15:03:09 -05:00
arch	Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm	2017-11-26 15:03:49 -08:00
block	treewide: setup_timer() -> timer_setup()	2017-11-21 15:57:07 -08:00
certs	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
crypto	Keys devel	2017-11-24 11:54:11 +11:00
Documentation	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-26 14:11:54 -08:00
drivers	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-26 14:39:20 -08:00
firmware	kbuild: remove all dummy assignments to obj-	2017-11-18 11:46:06 +09:00
fs	VFS: Handle lazytime in do_mount()	2017-12-09 20:16:33 -05:00
include	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-26 14:39:20 -08:00
init	EXPERT Kconfig menu: fix broken EXPERT menu	2017-11-17 16:10:05 -08:00
ipc	Merge branch 'akpm' (patches from Andrew)	2017-11-17 16:56:17 -08:00
kernel	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-26 14:39:20 -08:00
lib	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-25 08:37:16 -10:00
mm	mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed.	2017-12-18 15:03:09 -05:00
net	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-25 08:37:16 -10:00
samples	kbuild: remove all dummy assignments to obj-	2017-11-18 11:46:06 +09:00
scripts	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-25 08:37:16 -10:00
security	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-25 08:37:16 -10:00
sound	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-25 08:37:16 -10:00
tools	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-11-26 14:11:54 -08:00
usr	initramfs: fix initramfs rebuilds w/ compression after disabling	2017-11-03 07:39:19 -07:00
virt	Trimmed second batch of KVM changes for Linux 4.15	2017-11-24 19:44:25 -10:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes	.gitattributes: set git diff driver for C source code files	2016-10-07 18:46:30 -07:00
.gitignore	Kbuild misc updates for v4.15	2017-11-17 17:51:33 -08:00
.mailmap	Add Jason Gunthorpe as co-maintainer of the RDMA stack	2017-11-17 09:36:18 -08:00
COPYING
CREDITS	MAINTAINERS: update TPM driver infrastructure changes	2017-11-09 17:58:40 -08:00
Kbuild	Kbuild updates for v4.15	2017-11-17 17:45:29 -08:00
Kconfig	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
MAINTAINERS	RTC for 4.15	2017-11-22 20:58:23 -10:00
Makefile	Linux 4.15-rc1	2017-11-26 16:01:47 -08:00
README	README: add a new README file, pointing to the Documentation/	2016-10-24 08:12:35 -02:00

README

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.