Skip to content
This repository has been archived by the owner on Sep 24, 2020. It is now read-only.

ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors #63

Merged
merged 1 commit into from
Jun 29, 2017
Merged

ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors #63

merged 1 commit into from
Jun 29, 2017

Conversation

bgilbert
Copy link

@koct9i @bgilbert
ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors
53bcfff 
I've got another report about breaking ext4 by ENOMEM error returned from
ext4_mb_load_buddy() caused by memory shortage in memory cgroup.
This time inside ext4_discard_preallocations().

This patch replaces ext4_error() with ext4_warning() where errors returned
from ext4_mb_load_buddy() are not fatal and handled by caller:
* ext4_mb_discard_group_preallocations() - called before generating ENOSPC,
  we'll try to discard other group or return ENOSPC into user-space.
* ext4_trim_all_free() - just stop trimming and return ENOMEM from ioctl.

Some callers cannot handle errors, thus __GFP_NOFAIL is used for them:
* ext4_discard_preallocations()
* ext4_mb_discard_lg_preallocations()

Fixes: adb7ef6 ("ext4: use __GFP_NOFAIL in ext4_free_blocks()")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
@bgilbert bgilbert merged commit 75b1c04 into coreos:v4.11.8-coreos Jun 29, 2017
@bgilbert bgilbert deleted the v4.11.8-coreos branch June 29, 2017 18:56
coreosbot pushed a commit that referenced this pull request Feb 11, 2020
@gregkh
ipc/msg.c: consolidate all xxxctl_down() functions
078dd73 
commit 889b331 upstream.

A use of uninitialized memory in msgctl_down() because msqid64 in
ksys_msgctl hasn't been initialized.  The local | msqid64 | is created in
ksys_msgctl() and then passed into msgctl_down().  Along the way msqid64
is never initialized before msgctl_down() checks msqid64->msg_qbytes.

KUMSAN(KernelUninitializedMemorySantizer, a new error detection tool)
reports:

==================================================================
BUG: KUMSAN: use of uninitialized memory in msgctl_down+0x94/0x300
Read of size 8 at addr ffff88806bb97eb8 by task syz-executor707/2022

CPU: 0 PID: 2022 Comm: syz-executor707 Not tainted 5.2.0-rc4+ #63
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
 dump_stack+0x75/0xae
 __kumsan_report+0x17c/0x3e6
 kumsan_report+0xe/0x20
 msgctl_down+0x94/0x300
 ksys_msgctl.constprop.14+0xef/0x260
 do_syscall_64+0x7e/0x1f0
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4400e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd869e0598 EFLAGS: 00000246 ORIG_RAX: 0000000000000047
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000401970
R13: 0000000000401a00 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0001aee5c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x100000000000000()
raw: 0100000000000000 0000000000000000 ffffffff01ae0101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kumsan: bad access detected
==================================================================

Syzkaller reproducer:
msgctl$IPC_RMID(0x0, 0x0)

C reproducer:
// autogenerated by syzkaller (https://github.com/google/syzkaller)

int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  syscall(__NR_msgctl, 0, 0, 0);
  return 0;
}

[natechancellor@gmail.com: adjust indentation in ksys_msgctl]
  Link: ClangBuiltLinux#829
  Link: http://lkml.kernel.org/r/20191218032932.37479-1-natechancellor@gmail.com
Link: http://lkml.kernel.org/r/20190613014044.24234-1-shuaibinglu@126.com
Signed-off-by: Lu Shuaibing <shuaibinglu@126.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: NeilBrown <neilb@suse.com>
From: Andrew Morton <akpm@linux-foundation.org>
Subject: ipc/msg.c: consolidate all xxxctl_down() functions

Each line here overflows 80 cols by exactly one character.  Delete one tab
per line to fix.

Cc: Shaohua Li <shli@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sign up for free to subscribe to this conversation on GitHub. Already have an account? Sign in.
Reviewers

@dm0- dm0- dm0- approved these changes

Assignees
No one assigned
Labels
None yet
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
3 participants
@bgilbert @dm0- @koct9i