=====================================================
BUG: KMSAN: uninit-value in strnchr+0x90/0xd0 lib/string.c:387
 strnchr+0x90/0xd0 lib/string.c:387
 bpf_bprintf_prepare+0x1c2/0x23c0 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+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run224+0xb5/0xe0 kernel/bpf/core.c:2237
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420
 __bpf_trace_rss_stat+0x27/0x40 include/trace/events/kmem.h:384
 trace_rss_stat include/trace/events/kmem.h:384 [inline]
 mm_trace_rss_stat mm/memory.c:180 [inline]
 add_mm_counter include/linux/mm.h:2603 [inline]
 do_anonymous_page mm/memory.c:4478 [inline]
 do_pte_missing mm/memory.c:3878 [inline]
 handle_pte_fault mm/memory.c:5300 [inline]
 __handle_mm_fault mm/memory.c:5441 [inline]
 handle_mm_fault+0xc66f/0xce10 mm/memory.c:5606
 do_user_addr_fault arch/x86/mm/fault.c:1383 [inline]
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x2a0/0x6f0 arch/x86/mm/fault.c:1533
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623
 rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:65
 copy_to_user include/linux/uaccess.h:191 [inline]
 rng_dev_read+0xad9/0x1200 drivers/char/hw_random/core.c:265
 do_loop_readv_writev fs/read_write.c:761 [inline]
 vfs_readv+0x92d/0xea0 fs/read_write.c:934
 do_preadv fs/read_write.c:1049 [inline]
 __do_sys_preadv fs/read_write.c:1099 [inline]
 __se_sys_preadv fs/read_write.c:1094 [inline]
 __x64_sys_preadv+0x2e5/0x500 fs/read_write.c:1094
 x64_sys_call+0x3524/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:296
 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+0x77/0x7f

Local variable stack created at:
 __bpf_prog_run224+0x45/0xe0 kernel/bpf/core.c:2237
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420

CPU: 1 PID: 6081 Comm: syz-executor.3 Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================