syzbot


KMSAN: uninit-value in bpf_prog_test_run_xdp

Status: upstream: reported C repro on 2024/03/10 09:16
Subsystems: bpf net
[Documentation on labels]
Reported-by: syzbot+6856926fbb5e9b794e5c@syzkaller.appspotmail.com
First crash: 41d, last: 23d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp 0 (1) 2024/03/10 09:16
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Write in bpf_prog_test_run_xdp bpf net C done 18 792d 810d 22/26 fixed on 2023/02/24 13:50
linux-6.1 BUG: unable to handle kernel paging request in bpf_prog_test_run_xdp 1 155d 155d 0/3 auto-obsoleted due to no activity on 2024/02/21 19:18
Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/03/24 03:58 20m retest repro upstream report log

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in bpf_prog_test_run_xdp+0x1758/0x1a30 net/bpf/test_run.c:1277
 bpf_prog_test_run_xdp+0x1758/0x1a30 net/bpf/test_run.c:1277
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 bpf_test_run+0x515/0xaf0
 bpf_prog_test_run_xdp+0xea5/0x1a30 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 ___bpf_prog_run+0x76dd/0xdb80
 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2227
 bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
 __bpf_prog_run include/linux/filter.h:651 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x42d/0xaf0 net/bpf/test_run.c:421
 bpf_prog_test_run_xdp+0xea5/0x1a30 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 ___bpf_prog_run+0x8567/0xdb80
 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2227
 bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
 __bpf_prog_run include/linux/filter.h:651 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x42d/0xaf0 net/bpf/test_run.c:421
 bpf_prog_test_run_xdp+0xea5/0x1a30 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Local variable stack created at:
 __bpf_prog_run512+0x45/0xe0 kernel/bpf/core.c:2227
 bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
 __bpf_prog_run include/linux/filter.h:651 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x42d/0xaf0 net/bpf/test_run.c:421

CPU: 0 PID: 5009 Comm: syz-executor369 Not tainted 6.8.0-rc7-syzkaller-00142-g3aaa8ce7a335 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/08 15:48 upstream 3aaa8ce7a335 cf82cde1 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bpf_prog_test_run_xdp
2024/03/06 09:06 upstream 29cd507cbec2 f39a7eed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bpf_prog_test_run_xdp
* Struck through repros no longer work on HEAD.