Messages in this thread | | | Subject | Re: WARNING in bpf_int_jit_compile | From | Daniel Borkmann <> | Date | Mon, 28 May 2018 01:17:17 +0200 |
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On 05/26/2018 11:29 AM, syzbot wrote: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 62d18ecfa641 Merge tag 'arm64-fixes' of git://git.kernel.o.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14c6bf57800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=982e2df1b9e60b02 > dashboard link: https://syzkaller.appspot.com/bug?extid=9e762b52dd17e616a7a5 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=130e42b7800000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+9e762b52dd17e616a7a5@syzkaller.appspotmail.com > > RAX: ffffffffffffffda RBX: 0000000002542914 RCX: 0000000000455a09 > RDX: 0000000000000048 RSI: 0000000020000240 RDI: 0000000000000005 > RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 > R13: 0000000000000046 R14: 00000000006f4730 R15: 0000000000000023 > WARNING: CPU: 0 PID: 4752 at include/linux/filter.h:667 bpf_jit_binary_lock_ro include/linux/filter.h:667 [inline] > WARNING: CPU: 0 PID: 4752 at include/linux/filter.h:667 bpf_int_jit_compile+0xbf7/0xef7 arch/x86/net/bpf_jit_comp.c:1271 > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 4752 Comm: syz-executor0 Not tainted 4.17.0-rc6+ #67 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1b9/0x294 lib/dump_stack.c:113 > panic+0x22f/0x4de kernel/panic.c:184 > __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 > report_bug+0x252/0x2d0 lib/bug.c:186 > fixup_bug arch/x86/kernel/traps.c:178 [inline] > do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 > RIP: 0010:bpf_jit_binary_lock_ro include/linux/filter.h:667 [inline]
Been looking into this last Friday already. What seems to happen here is that there's fault injection from inside set_memory_ro(), meaning it will eventually return an error there, and we throw a WARN_ON_ONCE() to bark that making the memory read-only didn't work out. I'd be in preference to notify the user on such issue rather than keeping completely silent about it so that there's awareness that read-only protections are not in place / guaranteed.
> RIP: 0010:bpf_int_jit_compile+0xbf7/0xef7 arch/x86/net/bpf_jit_comp.c:1271 > RSP: 0018:ffff8801d85ff920 EFLAGS: 00010293 > RAX: ffff8801d78c40c0 RBX: 0000000000000046 RCX: ffffffff81445d89 > RDX: 0000000000000000 RSI: ffffffff81445d97 RDI: 0000000000000005 > RBP: ffff8801d85ffa40 R08: ffff8801d78c40c0 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: ffffc9000194e002 > R13: ffff8801d85ffa18 R14: 00000000fffffff4 R15: 0000000000000003 > bpf_prog_select_runtime+0x131/0x640 kernel/bpf/core.c:1541 > bpf_prog_load+0x16c2/0x2070 kernel/bpf/syscall.c:1333 > __do_sys_bpf kernel/bpf/syscall.c:2073 [inline] > __se_sys_bpf kernel/bpf/syscall.c:2035 [inline] > __x64_sys_bpf+0x389/0x4c0 kernel/bpf/syscall.c:2035 > do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x455a09 > RSP: 002b:00007ffec3da2868 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 > RAX: ffffffffffffffda RBX: 0000000002542914 RCX: 0000000000455a09 > RDX: 0000000000000048 RSI: 0000000020000240 RDI: 0000000000000005 > RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 > R13: 0000000000000046 R14: 00000000006f4730 R15: 0000000000000023 > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. >
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