On Wed, Nov 05, 2025 at 03:23:18PM +0100, Petr Mladek wrote: > 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
Looks good to me. Reviewed-by: Aaron Tomlin <[email protected]> -- Aaron Tomlin
