While one must hold RCU-sched (aka. preempt_disable) for find_symbol() one must equally hold it over the use of the object returned.
The moment you release the RCU-sched read lock, the object can be dead and gone. Cc: Seth Jennings <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Miroslav Benes <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: Rusty Russell <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- kernel/livepatch/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -248,11 +248,12 @@ static int klp_find_external_symbol(stru /* first, check if it's an exported symbol */ preempt_disable(); sym = find_symbol(name, NULL, NULL, true, true); - preempt_enable(); if (sym) { *addr = sym->value; + preempt_enable(); return 0; } + preempt_enable(); /* otherwise check if it's in another .o within the patch module */ return klp_find_object_symbol(pmod->name, name, addr); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
