From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 EF88934E75A; Wed, 30 Sep 2026 19:12:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795559; cv=none; b=UWFixMFa5ShbwyHYyk5gG1D5T4c3uBfOnjFhfiWii1UCvEShdgsfjTuJIYcosUO6baVO/cz1YR7OJAb2wk9TvLxM5v5rYgrkpj2/7XFf13uKuwLuRY20PBCM3XGrl+bb0A8EY1o5Ihh2/BmJDG6bCPWMYNh6bK/vBeP5/JVUYTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795559; c=relaxed/simple; bh=SWhTf8RXn3A1XUmnjpMd2o6aZnB4KB4DTEC23mad4+g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uLmilTqTxqDV7nyKr9Z2eItLXmt78Rkhm5l4qsbbCMXAINBsV+n2JrxX3AZFc5BVBu3JR+pa6afNwC7KKtfCMvWrSDSa88r+JgZ2thEHsvIYBioTkq/zih1u4nKCgXDTbULzZSz6Cdu5PG/aZzEtri3PUUmuHyq8qPuwHc/BVzg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YjsHy2aY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YjsHy2aY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FF291F000FF; Wed, 30 Sep 2026 19:12:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790795557; bh=nZGJkiRdgu1uwGrqgBcgjqst/HwLy0HSNRPnIobgSGg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YjsHy2aYe296kKo8UNJ2c7gT05Z0AjTxsKwX5+yzwZwp5en2j2pZ9JvtsxngIE0nu rkQ5i87+wGF+apa5NDdfSBSz2rtkVEq6s1eaTW1hzRpWCpTePv0PCq4RxjFkd+hkxU FD/CYCtqPf1xrIcTETFEOo1cWeERZ6vcXv/Dnj8k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Donggeun Yoo , Steven Rostedt Subject: [PATCH 6.6 0602/1193] tracing: Fix memory corruption from the histogram stacktrace modifier Date: Wed, 30 Sep 2026 17:21:26 +0200 Message-ID: <20260930152447.620565810@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Donggeun Yoo commit a5e70ba87ca8ebc79b4e63de302d03b0625fe153 upstream. parse_field() sets HIST_FIELD_FL_STACKTRACE from the ".stacktrace" modifier before it looks the field name up, and nothing afterwards checks that the name resolved to a field which holds a stacktrace. create_hist_field() picks HIST_FIELD_FN_STACK on the strength of the field pointer alone, which reads a __data_loc word from the record and follows its low 16 bits as an offset into the same record. event_hist_trigger() takes the first word there as an entry count and copies that many longs into a 31 entry array: n_entries = *stack; memcpy(entries, ++stack, n_entries * sizeof(unsigned long)); Neither end of that copy is bounded, and the count is whatever the event holds at the offset, so any field will do: # cd /sys/kernel/tracing/events/sched/sched_process_fork # echo 'hist:keys=parent_pid.stacktrace' > trigger # (true) BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:rb_insert_color+0x18/0x130 timerqueue_linked_add+0x7e/0xd0 enqueue_hrtimer+0x39/0xb0 __hrtimer_run_queues+0x10f/0x1f0 RIP: 0010:memcpy+0xc/0x30 event_hist_trigger+0x165/0x690 The timer interrupt landed on the rbtree the copy had already run over. No debug options are needed for this; KASAN reports the same write as an out-of-bounds read of 13835058055416381440 bytes. Documentation/trace/histogram.rst already states the rule, "must be a long[] type", so enforce it once the name has been resolved. Names which resolve to no field at all, "hitcount.stacktrace" and the common_* pseudo-fields, are refused for the same reason: they hold no stacktrace to read. Cc: stable@vger.kernel.org Fixes: cc5fc8bfc961 ("tracing/histogram: Add stacktrace type") Link: https://patch.msgid.link/20260907155045.692664-2-donggeunyoo.kernel@gmail.com Signed-off-by: Donggeun Yoo Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -2307,6 +2307,7 @@ parse_field(struct hist_trigger_data *hi struct ftrace_event_field *field = NULL; char *field_name, *modifier, *str; struct trace_array *tr = file->tr; + bool stack_modifier = false; modifier = str = kstrdup(field_str, GFP_KERNEL); if (!modifier) @@ -2329,9 +2330,10 @@ parse_field(struct hist_trigger_data *hi *flags |= HIST_FIELD_FL_EXECNAME; else if (strcmp(modifier, "syscall") == 0) *flags |= HIST_FIELD_FL_SYSCALL; - else if (strcmp(modifier, "stacktrace") == 0) + else if (strcmp(modifier, "stacktrace") == 0) { *flags |= HIST_FIELD_FL_STACKTRACE; - else if (strcmp(modifier, "log2") == 0) + stack_modifier = true; + } else if (strcmp(modifier, "log2") == 0) *flags |= HIST_FIELD_FL_LOG2; else if (strcmp(modifier, "usecs") == 0) *flags |= HIST_FIELD_FL_TIMESTAMP_USECS; @@ -2398,6 +2400,12 @@ parse_field(struct hist_trigger_data *hi } } } + + if (stack_modifier && + (!field || field->filter_type != FILTER_STACKTRACE)) { + hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str)); + field = ERR_PTR(-EINVAL); + } out: kfree(str);