modbuildid is never set when kallsyms_lookup_buildid is returning via successful ftrace_mod_address_lookup.
This leads to an uninitialized pointer dereference on x86 when CONFIG_STACKTRACE_BUILD_ID=y inside __sprint_symbol. Prevent this by always initializing modbuildid. Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220717 Signed-off-by: Maurice Hieronymus <[email protected]> --- include/linux/ftrace.h | 4 ++-- kernel/kallsyms.c | 2 +- kernel/trace/ftrace.c | 8 +++++++- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 770f0dc993cc..ed673fa2536b 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -87,11 +87,11 @@ struct ftrace_hash; defined(CONFIG_DYNAMIC_FTRACE) int ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym); + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym); #else static inline int ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym) + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym) { return 0; } diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 049e296f586c..5ca69eafda7a 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -382,7 +382,7 @@ static int kallsyms_lookup_buildid(unsigned long addr, if (!ret) ret = ftrace_mod_address_lookup(addr, symbolsize, - offset, modname, namebuf); + offset, modname, modbuildid, namebuf); return ret; } diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index ef2d5dca6f70..6eba92a52261 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -7752,7 +7752,7 @@ ftrace_func_address_lookup(struct ftrace_mod_map *mod_map, int ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym) + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym) { struct ftrace_mod_map *mod_map; int ret = 0; @@ -7764,6 +7764,12 @@ ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, if (ret) { if (modname) *modname = mod_map->mod->name; + if (modbuildid) +#ifdef CONFIG_STACKTRACE_BUILD_ID + *modbuildid = mod_map->mod->build_id; +#else + *modbuildid = NULL; +#endif break; } } -- 2.50.1
