kallsyms_lookup_buildid() copies the symbol name into the given buffer so that it can be safely read anytime later. But it just copies pointers to mod->name and mod->build_id which might get reused after the related struct module gets removed.
The lifetime of struct module is synchronized using RCU. Take the rcu read lock for the entire __sprint_symbol(). Signed-off-by: Petr Mladek <[email protected]> --- kernel/kallsyms.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index ff7017337535..1fda06b6638c 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -468,6 +468,9 @@ static int __sprint_symbol(char *buffer, unsigned long address, unsigned long offset, size; int len; + /* Prevent module removal until modname and modbuildid are printed */ + guard(rcu)(); + address += symbol_offset; len = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid, buffer); -- 2.51.1
