diff options
| author | Aaron Ahmed <aarnahmd@amazon.com> | 2026-10-16 23:04:03 +0000 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-10-19 10:46:23 -0400 |
| commit | e1f339ff3b83857b93baf8b88186275a413d445e (patch) | |
| tree | 71536e87f47e71605b3f7548e583628b8b516c86 /kernel/trace | |
| parent | c738829502be3f71500b9e70e04f8eee49734d95 (diff) | |
ftrace: Initialize modname and offset in print_rec()
print_rec() leaves 'modname' and 'offset' uninitialized and
kallsyms_lookup() only sets them on success. When the lookup fails like
when a module is being loaded or unloaded, 'modname' holds a garbage
value, passes the 'if (modname)' check, and is dereferenced by
seq_printf().
Oops: general protection fault
RIP: 0010:string+0x48/0xe0
Call Trace:
vsnprintf+0x1f5/0x650
seq_printf+0x8e/0xb0
print_rec+0x6c/0xc0
t_show+0x4c/0x440
seq_read_iter+0x119/0x480
This can be triggered by reading available_filter_functions while a
module is being loaded or unloaded.
Initialize both variables so a failed lookup skips the module name.
Cc: stable@vger.kernel.org
Fixes: b39181f7c690 ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function")
Link: https://patch.msgid.link/20261016230403.4916-1-aarnahmd@amazon.com
Tested-by: Gavin Inglis <giinglis@amazon.com>
Signed-off-by: Aaron Ahmed <aarnahmd@amazon.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ftrace.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b2597eb9581b..c7d74b33d36d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4431,9 +4431,9 @@ subsys_initcall(ftrace_check_for_weak_functions); static int print_rec(struct seq_file *m, unsigned long ip) { - unsigned long offset; + unsigned long offset = 0; char str[KSYM_SYMBOL_LEN]; - char *modname; + char *modname = NULL; const char *ret; ret = kallsyms_lookup(ip, NULL, &offset, &modname, str); |