Messages in this thread |  | | Subject | Re: [syzbot] WARNING: suspicious RCU usage in bpf_get_current_cgroup_id | From | Yonghong Song <> | Date | Sun, 25 Jul 2021 23:46:30 -0700 |
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On 7/24/21 12:47 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: d6371c76e20d bpf: Fix OOB read when printing XDP link fdinfo > git tree: bpf > console output: https://syzkaller.appspot.com/x/log.txt?x=146597f2300000 > kernel config: https://syzkaller.appspot.com/x/.config?x=6da37c7627210105 > dashboard link: https://syzkaller.appspot.com/bug?extid=7ee5c2c09c284495371f > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=126b7c40300000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1616cf6a300000 > > The issue was bisected to: > > commit 79a7f8bdb159d9914b58740f3d31d602a6e4aca8 > Author: Alexei Starovoitov <ast@kernel.org> > Date: Fri May 14 00:36:03 2021 +0000 > > bpf: Introduce bpf_sys_bpf() helper and program type. > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14a73112300000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=16a73112300000 > console output: https://syzkaller.appspot.com/x/log.txt?x=12a73112300000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+7ee5c2c09c284495371f@syzkaller.appspotmail.com > Fixes: 79a7f8bdb159 ("bpf: Introduce bpf_sys_bpf() helper and program type.") > > ============================= > WARNING: suspicious RCU usage > 5.14.0-rc1-syzkaller #0 Not tainted > ----------------------------- > include/linux/cgroup.h:481 suspicious rcu_dereference_check() usage!
Looks like we may miss rcu_read_lock/rcu_read_unlock in this function, static inline u32 bpf_prog_run_pin_on_cpu(const struct bpf_prog *prog, const void *ctx) { u32 ret;
migrate_disable(); ret = __BPF_PROG_RUN(prog, ctx, bpf_dispatcher_nop_func); migrate_enable(); return ret; }
Will provide a fix soon.
> > other info that might help us debug this: > > > rcu_scheduler_active = 2, debug_locks = 1 > no locks held by syz-executor499/8468. > > stack backtrace: > CPU: 1 PID: 8468 Comm: syz-executor499 Not tainted 5.14.0-rc1-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 > task_css_set include/linux/cgroup.h:481 [inline] > task_dfl_cgroup include/linux/cgroup.h:550 [inline] > ____bpf_get_current_cgroup_id kernel/bpf/helpers.c:356 [inline] > bpf_get_current_cgroup_id+0x1ce/0x210 kernel/bpf/helpers.c:354 > bpf_prog_08c4887f705f20b8+0x10/0x824 > bpf_dispatcher_nop_func include/linux/bpf.h:687 [inline] > bpf_prog_run_pin_on_cpu include/linux/filter.h:624 [inline] > bpf_prog_test_run_syscall+0x2cf/0x5f0 net/bpf/test_run.c:954 > bpf_prog_test_run kernel/bpf/syscall.c:3207 [inline] > __sys_bpf+0x1993/0x53b0 kernel/bpf/syscall.c:4487 > __do_sys_bpf kernel/bpf/syscall.c:4573 [inline] > __se_sys_bpf kernel/bpf/syscall.c:4571 [inline] > __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4571 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x44d6a9 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 18 00 00 90 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f32119dd318 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 > RAX: ffffffffffffffda RBX: 00000000004cb3e8 RCX: 000000000044d6a9 > RDX: 0000000000000048 RSI: 0000000020000500 RDI: 000000000000000a > RBP: 00000000004cb3e0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 656c6c616b7a7973 > R13: 00007ffeb7672e8f R14: 00007f32119dd400 R15: 0000000000022000 > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches >
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