From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org, kernel test robot <lkp@intel.com>
Subject: [for-next][PATCH 03/12] tracing: Have the user copy of synthetic event address use correct context
Date: Wed, 01 Nov 2023 17:37:21 -0400 [thread overview]
Message-ID: <20231101213802.233842141@goodmis.org> (raw)
In-Reply-To: 20231101213718.381015321@goodmis.org
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
A synthetic event is created by the synthetic event interface that can
read both user or kernel address memory. In reality, it reads any
arbitrary memory location from within the kernel. If the address space is
in USER (where CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE is set) then
it uses strncpy_from_user_nofault() to copy strings otherwise it uses
strncpy_from_kernel_nofault().
But since both functions use the same variable there's no annotation to
what that variable is (ie. __user). This makes sparse complain.
Quiet sparse by typecasting the strncpy_from_user_nofault() variable to
a __user pointer.
Link: https://lore.kernel.org/linux-trace-kernel/20231031151033.73c42e23@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 0934ae9977c2 ("tracing: Fix reading strings from synthetic events");
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311010013.fm8WTxa5-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace_events_synth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 14cb275a0bab..846e02c0fb59 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -452,7 +452,7 @@ static unsigned int trace_string(struct synth_trace_event *entry,
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
if ((unsigned long)str_val < TASK_SIZE)
- ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
+ ret = strncpy_from_user_nofault(str_field, (const void __user *)str_val, STR_VAR_LEN_MAX);
else
#endif
ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
--
2.42.0
next prev parent reply other threads:[~2023-11-01 21:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20231101213718.381015321@goodmis.org>
2023-11-01 21:37 ` [for-next][PATCH 01/12] tracing: Have trace_event_file have ref counters Steven Rostedt
2023-11-01 21:37 ` Steven Rostedt [this message]
2023-11-01 21:37 ` [for-next][PATCH 05/12] eventfs: Remove "is_freed" union with rcu head Steven Rostedt
2023-11-01 21:37 ` [for-next][PATCH 10/12] eventfs: Delete eventfs_inode when the last dentry is freed Steven Rostedt
2023-11-01 21:37 ` [for-next][PATCH 12/12] eventfs: Use simple_recursive_removal() to clean up dentries Steven Rostedt
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