On 3/7/24 12:30 AM, syzbot wrote:
Hello, syzbot found the following issue on: HEAD commit: 04b8076df253 Merge tag 'firewire-fixes-6.8-rc7' of git://g.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=10bb9306180000 kernel config: https://syzkaller.appspot.com/x/.config?x=80c7a82a572c0de3 dashboard link: https://syzkaller.appspot.com/bug?extid=9b8be5e35747291236c8 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11093316180000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15a53082180000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a4610b1ff2a7/disk-04b8076d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/991e9d902d39/vmlinux-04b8076d.xz kernel image: https://storage.googleapis.com/syzbot-assets/a5b8e8e98121/bzImage-04b8076d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9b8be5e35747291236c8@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== BUG: KMSAN: uninit-value in strnchr+0x90/0xd0 lib/string.c:388 strnchr+0x90/0xd0 lib/string.c:388 bpf_bprintf_prepare+0x1c2/0x23b0 kernel/bpf/helpers.c:829 ____bpf_trace_printk kernel/trace/bpf_trace.c:385 [inline] bpf_trace_printk+0xec/0x3e0 kernel/trace/bpf_trace.c:375 ___bpf_prog_run+0x2180/0xdb80 kernel/bpf/core.c:1986 __bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2225
This is the same as the dev_map_lookup_elem report when running in interpreter mode. It loads a different program to call bpf_trace_printk instead.
0: (6a) *(u16 *)(r10 -8) = 628106613 1: (bf) r1 = r10 2: (07) r1 += -8 3: (b7) r2 = 5 4: (bf) r3 = r1 5: (85) call bpf_trace_printk#-315920 6: (b7) r0 = 0 7: (95) exit #syz dup: [syzbot] [bpf?] [net?] KMSAN: uninit-value in dev_map_lookup_elem
