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From: Muchun Song In-Reply-To: <20230421174054.3434533-1-roman.gushchin@linux.dev> Date: Sun, 23 Apr 2023 10:25:58 +0800 Cc: Linux Memory Management List , Andrew Morton , Johannes Weiner , Michal Hocko , Shakeel Butt , linux-kernel@vger.kernel.org, syzbot+774c29891415ab0fd29d@syzkaller.appspotmail.com, Dmitry Vyukov Content-Transfer-Encoding: quoted-printable Message-Id: References: <00000000000058b63f05f9d98811@google.com> <20230421174054.3434533-1-roman.gushchin@linux.dev> To: Roman Gushchin X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 96409180004 X-Stat-Signature: 7qfzi6g67eekh1ogohtusaz1fmwnfy4n X-HE-Tag: 1682216766-470840 X-HE-Meta: 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 pGLESWAn ytDT67K5PMetpv7byFLGNZv3K+f8p6UbATx6siqTz1XLFf4NSaGbeF9hOXLCzU1THFpEUcHxhl4IUOiVC+WQzDxuPBrfY3N0fWo9fyHK3IZUZxxluMfhLl1dOYQXJshVHwBj1+3bBS1oSXpSEH7pyeljvmGEdjPkSEXzZbe+4EhMRfTyRYNrCe4gAkVHDD33nNTYLDVzTZoVQ07Jw7wjMRzfENLjsWFQEzoyKOrE4bmPQFd+mLY/ajaEFQBiDDniRW0QA780qELR9Mf2ge4WcVnlvPHAb5ovejKZtMFQXZ4DZUzJ2bb+7SbVvhiAB/DWP5lP76dHl5vGBrV2WuuULFdRxp4CEiNqGEu88Tqpy+YTEI0/YPs2D29vIfib97qo7CY5BrilllOyrmaCYDxRaimd00T04DcQltdqdT/QPtx3AfuBJo9iwH6FayQ6X26vZt9N6q0MGdDX3E4U= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Apr 22, 2023, at 01:40, Roman Gushchin = wrote: >=20 > KCSAN found an issue in obj_stock_flush_required(): > stock->cached_objcg can be reset between the check and dereference: >=20 > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > BUG: KCSAN: data-race in drain_all_stock / drain_obj_stock >=20 > 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 >=20 > 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 >=20 > value changed: 0xffff8881382d52c0 -> 0xffff888138893740 >=20 > 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 >=20 > Fix it by reading the cached_objcg with READ_ONCE(). >=20 > Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API") > Reported-by: syzbot+774c29891415ab0fd29d@syzkaller.appspotmail.com > Reported-by: Dmitry Vyukov > Link: = https://lore.kernel.org/linux-mm/CACT4Y+ZfucZhM60YPphWiCLJr6+SGFhT+jjm8k1P= -a_8Kkxsjg@mail.gmail.com/T/#t > Signed-off-by: Roman Gushchin Acked-by: Muchun Song Thanks.