Re: [PATCH] tracing: kprobe-event: Fix null-ptr-deref in trace_kprobe_create_internal()
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date: 2025-09-17 13:36:35
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On Tue, 16 Sep 2025 15:58:16 +0800 Wang Liang [off-list ref] wrote:
A crash was observed with the following output: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 UID: 0 PID: 2899 Comm: syz.2.399 Not tainted 6.17.0-rc5+ #5 PREEMPT(none) RIP: 0010:trace_kprobe_create_internal+0x3fc/0x1440 kernel/trace/trace_kprobe.c:911 Call Trace: <TASK> trace_kprobe_create_cb+0xa2/0xf0 kernel/trace/trace_kprobe.c:1089 trace_probe_create+0xf1/0x110 kernel/trace/trace_probe.c:2246 dyn_event_create+0x45/0x70 kernel/trace/trace_dynevent.c:128 create_or_delete_trace_kprobe+0x5e/0xc0 kernel/trace/trace_kprobe.c:1107 trace_parse_run_command+0x1a5/0x330 kernel/trace/trace.c:10785 vfs_write+0x2b6/0xd00 fs/read_write.c:684 ksys_write+0x129/0x240 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x5d/0x2d0 arch/x86/entry/syscall_64.c:94 </TASK> Function kmemdup() may return NULL in trace_kprobe_create_internal(), add check for it's return value.
Oops, thanks for fixing! Let me pick this!
quoted hunk ↗ jump to hunk
Fixes: 33b4e38baa03 ("tracing: kprobe-event: Allocate string buffers from heap") Signed-off-by: Wang Liang <redacted> --- kernel/trace/trace_kprobe.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index ccae62d4fb91..fa60362a3f31 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c@@ -908,6 +908,8 @@ static int trace_kprobe_create_internal(int argc, const char *argv[], return -EINVAL; } buf = kmemdup(&argv[0][1], len + 1, GFP_KERNEL); + if (!buf) + return -ENOMEM; buf[len] = '\0'; ret = kstrtouint(buf, 0, &maxactive); if (ret || !maxactive) {-- 2.34.1
-- Masami Hiramatsu (Google) [off-list ref]