From: Shakeel Butt <shakeelb@google.com>
To: Roman Gushchin <roman.gushchin@linux.dev>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Muchun Song <muchun.song@linux.dev>,
linux-kernel@vger.kernel.org,
syzbot+774c29891415ab0fd29d@syzkaller.appspotmail.com,
Dmitry Vyukov <dvyukov@google.com>,
Yosry Ahmed <yosryahmed@google.com>
Subject: Re: [PATCH v2 1/2] mm: kmem: fix a NULL pointer dereference in obj_stock_flush_required()
Date: Wed, 3 May 2023 17:04:19 +0000 [thread overview]
Message-ID: <20230503170419.aedezirnlbtsaijv@google.com> (raw)
In-Reply-To: <20230502160839.361544-1-roman.gushchin@linux.dev>
On Tue, May 02, 2023 at 09:08:38AM -0700, Roman Gushchin wrote:
> KCSAN found an issue in obj_stock_flush_required():
> stock->cached_objcg can be reset between the check and dereference:
>
> ==================================================================
> BUG: KCSAN: data-race in drain_all_stock / drain_obj_stock
>
> write to 0xffff888237c2a2f8 of 8 bytes by task 19625 on cpu 0:
> drain_obj_stock+0x408/0x4e0 mm/memcontrol.c:3306
> refill_obj_stock+0x9c/0x1e0 mm/memcontrol.c:3340
> obj_cgroup_uncharge+0xe/0x10 mm/memcontrol.c:3408
> memcg_slab_free_hook mm/slab.h:587 [inline]
> __cache_free mm/slab.c:3373 [inline]
> __do_kmem_cache_free mm/slab.c:3577 [inline]
> kmem_cache_free+0x105/0x280 mm/slab.c:3602
> __d_free fs/dcache.c:298 [inline]
> dentry_free fs/dcache.c:375 [inline]
> __dentry_kill+0x422/0x4a0 fs/dcache.c:621
> dentry_kill+0x8d/0x1e0
> dput+0x118/0x1f0 fs/dcache.c:913
> __fput+0x3bf/0x570 fs/file_table.c:329
> ____fput+0x15/0x20 fs/file_table.c:349
> task_work_run+0x123/0x160 kernel/task_work.c:179
> resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
> exit_to_user_mode_loop+0xcf/0xe0 kernel/entry/common.c:171
> exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:203
> __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
> syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
> do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> read to 0xffff888237c2a2f8 of 8 bytes by task 19632 on cpu 1:
> obj_stock_flush_required mm/memcontrol.c:3319 [inline]
> drain_all_stock+0x174/0x2a0 mm/memcontrol.c:2361
> try_charge_memcg+0x6d0/0xd10 mm/memcontrol.c:2703
> try_charge mm/memcontrol.c:2837 [inline]
> mem_cgroup_charge_skmem+0x51/0x140 mm/memcontrol.c:7290
> sock_reserve_memory+0xb1/0x390 net/core/sock.c:1025
> sk_setsockopt+0x800/0x1e70 net/core/sock.c:1525
> udp_lib_setsockopt+0x99/0x6c0 net/ipv4/udp.c:2692
> udp_setsockopt+0x73/0xa0 net/ipv4/udp.c:2817
> sock_common_setsockopt+0x61/0x70 net/core/sock.c:3668
> __sys_setsockopt+0x1c3/0x230 net/socket.c:2271
> __do_sys_setsockopt net/socket.c:2282 [inline]
> __se_sys_setsockopt net/socket.c:2279 [inline]
> __x64_sys_setsockopt+0x66/0x80 net/socket.c:2279
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> value changed: 0xffff8881382d52c0 -> 0xffff888138893740
>
> Reported by Kernel Concurrency Sanitizer on:
> CPU: 1 PID: 19632 Comm: syz-executor.0 Not tainted 6.3.0-rc2-syzkaller-00387-g534293368afa #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
>
> Fix it by using READ_ONCE()/WRITE_ONCE() for all accesses to
> stock->cached_objcg.
>
> Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API")
> Reported-by: syzbot+774c29891415ab0fd29d@syzkaller.appspotmail.com
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Link:
> https://lore.kernel.org/linux-mm/CACT4Y+ZfucZhM60YPphWiCLJr6+SGFhT+jjm8k1P-a_8Kkxsjg@mail.gmail.com/T/#t
> Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Yosry Ahmed <yosryahmed@google.com>
> Cc: Shakeel Butt <shakeelb@google.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
prev parent reply other threads:[~2023-05-03 17:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-02 16:08 Roman Gushchin
2023-05-02 16:08 ` [PATCH v2 2/2] mm: memcg: use READ_ONCE()/WRITE_ONCE() to access stock->cached Roman Gushchin
2023-05-02 20:21 ` Yosry Ahmed
2023-05-03 17:06 ` Shakeel Butt
2023-05-02 20:15 ` [PATCH v2 1/2] mm: kmem: fix a NULL pointer dereference in obj_stock_flush_required() Yosry Ahmed
2023-05-02 21:38 ` Roman Gushchin
2023-05-02 22:10 ` Yosry Ahmed
2023-05-03 17:03 ` Shakeel Butt
2023-05-03 8:05 ` Dmitry Vyukov
2023-05-03 17:04 ` Shakeel Butt [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230503170419.aedezirnlbtsaijv@google.com \
--to=shakeelb@google.com \
--cc=akpm@linux-foundation.org \
--cc=dvyukov@google.com \
--cc=hannes@cmpxchg.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=muchun.song@linux.dev \
--cc=roman.gushchin@linux.dev \
--cc=syzbot+774c29891415ab0fd29d@syzkaller.appspotmail.com \
--cc=yosryahmed@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox