From nobody Fri Oct 3 21:53:28 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A4109269806; Sun, 24 Aug 2025 13:08:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756040887; cv=none; b=NV6r8Ftqow5ZOVJXf1h1Yb3WdcDoUT6GYNUYPF/OCw6N0Q8jNv8sZDirE+F+R917iZ1JvrseDXCLqIK8uqSQ77TAR3X7HkMs2MM7mR9qSvkUfXjUOy0MNGZ91Ih5f49mvebThp4gMVALU/3EghxUw0cJqj7U76aOd3XIV1X2cpM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756040887; c=relaxed/simple; bh=c/pmFE4hhHdYRQMOehbBMtIk9AjMFS+JxZ7MckvIVMM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XZryTECr6Y0LP6XRXcLrmJp9XxgawPpuMpnBKORpF2rgU3kKkx2USL9mjiB0L2aykwGUyHWlqj9f8NSB78a5s+B+GW6yFe/4p56LV+yPFGkz5JRo+LZezMn4jLaqHZjMpKpHQI+fn04Yk79lnypV0hFGxVFRtZ7jrdFN6ejOQIU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CMLqhO8Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CMLqhO8Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1A3AC4CEEB; Sun, 24 Aug 2025 13:08:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756040887; bh=c/pmFE4hhHdYRQMOehbBMtIk9AjMFS+JxZ7MckvIVMM=; h=From:To:Cc:Subject:Date:From; b=CMLqhO8YykEmBddsn1YaWApi85Vtax3IOM8A5OtISl56VsnwYsRIogHVJZNsDeWJx sGLwfH8I/jGN0HKUiLenRDinB1qGvTGkme1JfyOcjRFNJIgbtzY1QDVBdoMTZGrkW7 TLhBuvWQOJ3ZxKEv6/lZhIuUXQlVKBtLzLGvDgJc/1bNbez8AS46SSHDqhtKzf68EY OYMDlPy1y+HwKEC2XZ2EG5M/rdQC/DTrQs/rG9E1EsHFY8wPUWF0T3wxgRlE7HaBL4 CWkYghfcyCF/3ACTCVLM/MaFKdmlEVGYCsD2y7/G8cPYXYOEK96mu8K6syMW+H1A9e OvKx3AFqX+VNw== From: Mike Rapoport To: Andrew Morton Cc: Borislav Petkov , Dave Hansen , Ingo Molnar , "Liam R. Howlett" , Masami Hiramatsu , Mike Rapoport , Peter Zijlstra , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org Subject: [PATCH] init/main.c: fix boot time tracing crash Date: Sun, 24 Aug 2025 16:07:59 +0300 Message-ID: <20250824130759.1732736-1-rppt@kernel.org> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Mike Rapoport (Microsoft)" Steven Rostedt reported a crash with "ftrace=3Dfunction" kernel command line: [ 0.159269] BUG: kernel NULL pointer dereference, address: 0000000000000= 01c [ 0.160254] #PF: supervisor read access in kernel mode [ 0.160975] #PF: error_code(0x0000) - not-present page [ 0.161697] PGD 0 P4D 0 [ 0.162055] Oops: Oops: 0000 [#1] SMP PTI [ 0.162619] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.17.0-rc2-te= st-00006-g48d06e78b7cb-dirty #9 PREEMPT(undef) [ 0.164141] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.1= 6.3-debian-1.16.3-2 04/01/2014 [ 0.165439] RIP: 0010:kmem_cache_alloc_noprof (mm/slub.c:4237) [ 0.166186] Code: 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 55 48 89 e5 41 57 41 = 56 41 55 41 54 49 89 fc 53 48 83 e4 f0 48 83 ec 20 8b 05 c9 b6 7e 01 <44> 8= b 77 1c 65 4c 8b 2d b5 ea 20 02 4c 89 6c 24 18 41 89 f5 21 f0 [ 0.168811] RSP: 0000:ffffffffb2e03b30 EFLAGS: 00010086 [ 0.169545] RAX: 0000000001fff33f RBX: 0000000000000000 RCX: 00000000000= 00000 [ 0.170544] RDX: 0000000000002800 RSI: 0000000000002800 RDI: 00000000000= 00000 [ 0.171554] RBP: ffffffffb2e03b80 R08: 0000000000000004 R09: ffffffffb2e= 03c90 [ 0.172549] R10: ffffffffb2e03c90 R11: 0000000000000000 R12: 00000000000= 00000 [ 0.173544] R13: ffffffffb2e03c90 R14: ffffffffb2e03c90 R15: 00000000000= 00001 [ 0.174542] FS: 0000000000000000(0000) GS:ffff9d2808114000(0000) knlGS:= 0000000000000000 [ 0.175684] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.176486] CR2: 000000000000001c CR3: 000000007264c001 CR4: 00000000000= 200b0 [ 0.177483] Call Trace: [ 0.177828] [ 0.178123] mas_alloc_nodes (lib/maple_tree.c:176 (discriminator 2) lib/= maple_tree.c:1255 (discriminator 2)) [ 0.178692] mas_store_gfp (lib/maple_tree.c:5468) [ 0.179223] execmem_cache_add_locked (mm/execmem.c:207) [ 0.179870] execmem_alloc (mm/execmem.c:213 mm/execmem.c:313 mm/execmem.= c:335 mm/execmem.c:475) [ 0.180397] ? ftrace_caller (arch/x86/kernel/ftrace_64.S:169) [ 0.180922] ? __pfx_ftrace_caller (arch/x86/kernel/ftrace_64.S:158) [ 0.181517] execmem_alloc_rw (mm/execmem.c:487) [ 0.182052] arch_ftrace_update_trampoline (arch/x86/kernel/ftrace.c:266 = arch/x86/kernel/ftrace.c:344 arch/x86/kernel/ftrace.c:474) [ 0.182778] ? ftrace_caller_op_ptr (arch/x86/kernel/ftrace_64.S:182) [ 0.183388] ftrace_update_trampoline (kernel/trace/ftrace.c:7947) [ 0.184024] __register_ftrace_function (kernel/trace/ftrace.c:368) [ 0.184682] ftrace_startup (kernel/trace/ftrace.c:3048) [ 0.185205] ? __pfx_function_trace_call (kernel/trace/trace_functions.c:= 210) [ 0.185877] register_ftrace_function_nolock (kernel/trace/ftrace.c:8717) [ 0.186595] register_ftrace_function (kernel/trace/ftrace.c:8745) [ 0.187254] ? __pfx_function_trace_call (kernel/trace/trace_functions.c:= 210) [ 0.187924] function_trace_init (kernel/trace/trace_functions.c:170) [ 0.188499] tracing_set_tracer (kernel/trace/trace.c:5916 kernel/trace/t= race.c:6349) [ 0.189088] register_tracer (kernel/trace/trace.c:2391) [ 0.189642] early_trace_init (kernel/trace/trace.c:11075 kernel/trace/tr= ace.c:11149) [ 0.190204] start_kernel (init/main.c:970) [ 0.190732] x86_64_start_reservations (arch/x86/kernel/head64.c:307) [ 0.191381] x86_64_start_kernel (??:?) [ 0.191955] common_startup_64 (arch/x86/kernel/head_64.S:419) [ 0.192534] [ 0.192839] Modules linked in: [ 0.193267] CR2: 000000000000001c [ 0.193730] ---[ end trace 0000000000000000 ]--- The crash happens because on x86 ftrace allocations from execmem require maple tree to be initialized. Move maple tree initialization that depends only on slab availability earlier in boot so that it will happen right after mm_core_init(). Fixes: 5d79c2be5081 ("x86/ftrace: enable EXECMEM_ROX_CACHE for ftrace alloc= ations") Signed-off-by: Mike Rapoport (Microsoft) Reported-by: Steven Rostedt (Google) Reviewed-by: Liam R. Howlett Reviewed-by: Masami Hiramatsu (Google) Tested-by: Steven Rostedt (Google) --- init/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/init/main.c b/init/main.c index 0ee0ee7b7c2c..5753e9539ae6 100644 --- a/init/main.c +++ b/init/main.c @@ -956,6 +956,7 @@ void start_kernel(void) sort_main_extable(); trap_init(); mm_core_init(); + maple_tree_init(); poking_init(); ftrace_init(); =20 @@ -973,7 +974,6 @@ void start_kernel(void) "Interrupts were enabled *very* early, fixing it\n")) local_irq_disable(); radix_tree_init(); - maple_tree_init(); =20 /* * Set up housekeeping before setting up workqueues to allow the unbound base-commit: c17b750b3ad9f45f2b6f7e6f7f4679844244f0b9 --=20 2.50.1