diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2025-01-08 10:04:43 +0100 |
|---|---|---|
| committer | Petr Pavlu <petr.pavlu@suse.com> | 2025-03-10 11:54:45 +0100 |
| commit | 6593a2c990f251bce63ab8de0397405303e32381 (patch) | |
| tree | d6ac6434f1f92c1c4c654de90e1d26d039265060 | |
| parent | 2abf84f688bed9cb4d3208d9d538b3387d292972 (diff) | |
module: Use RCU in all users of __module_address().
__module_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.
Replace the preempt_disable() section around __module_address() with
RCU.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-15-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
| -rw-r--r-- | include/linux/kallsyms.h | 3 | ||||
| -rw-r--r-- | kernel/module/kallsyms.c | 5 | ||||
| -rw-r--r-- | kernel/module/main.c | 9 |
3 files changed, 4 insertions, 13 deletions
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 1c6a6c1704d8d..d5dd54c53ace6 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -55,12 +55,11 @@ static inline void *dereference_symbol_descriptor(void *ptr) if (is_ksym_addr((unsigned long)ptr)) return ptr; - preempt_disable(); + guard(rcu)(); mod = __module_address((unsigned long)ptr); if (mod) ptr = dereference_module_function_descriptor(mod, ptr); - preempt_enable(); #endif return ptr; } diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c index 0e8ec6486d95c..00a60796327c0 100644 --- a/kernel/module/kallsyms.c +++ b/kernel/module/kallsyms.c @@ -316,7 +316,7 @@ void * __weak dereference_module_function_descriptor(struct module *mod, /* * For kallsyms to ask for address resolution. NULL means not found. Careful - * not to lock to avoid deadlock on oopses, simply disable preemption. + * not to lock to avoid deadlock on oopses, RCU is enough. */ int module_address_lookup(unsigned long addr, unsigned long *size, @@ -330,7 +330,6 @@ int module_address_lookup(unsigned long addr, struct module *mod; guard(rcu)(); - preempt_disable(); mod = __module_address(addr); if (mod) { if (modname) @@ -348,8 +347,6 @@ int module_address_lookup(unsigned long addr, if (sym) ret = strscpy(namebuf, sym, KSYM_NAME_LEN); } - preempt_enable(); - return ret; } diff --git a/kernel/module/main.c b/kernel/module/main.c index aebb17e1bfb97..8a8b499730d86 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -3731,13 +3731,8 @@ const struct exception_table_entry *search_module_extables(unsigned long addr) */ bool is_module_address(unsigned long addr) { - bool ret; - - preempt_disable(); - ret = __module_address(addr) != NULL; - preempt_enable(); - - return ret; + guard(rcu)(); + return __module_address(addr) != NULL; } /** |