On Sat, Feb 28, 2015 at 10:24:51PM +0100, Peter Zijlstra wrote:
> As per the module core lockdep annotations:
>
> [ 18.034047] ---[ end trace 9294429076a9c673 ]---
> [ 18.047760] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS
> SE5C600.86B.02.02.0002.122320131210 12/23/2013
> [ 18.059228] ffffffff817d8676 ffff880036683c38 ffffffff8157e98b
> 0000000000000001
> [ 18.067541] 0000000000000000 ffff880036683c78 ffffffff8105fbc7
> ffff880036683c68
> [ 18.075851] ffffffffa0046b08 0000000000000000 ffffffffa0046d00
> ffffffffa0046cc8
> [ 18.084173] Call Trace:
> [ 18.086906] [<ffffffff8157e98b>] dump_stack+0x4f/0x7b
> [ 18.092649] [<ffffffff8105fbc7>] warn_slowpath_common+0x97/0xe0
> [ 18.099361] [<ffffffff8105fc2a>] warn_slowpath_null+0x1a/0x20
> [ 18.105880] [<ffffffff810ee502>] __module_address+0x1d2/0x1e0
> [ 18.112400] [<ffffffff81161153>] jump_label_module_notify+0x143/0x1e0
> [ 18.119710] [<ffffffff810814bf>] notifier_call_chain+0x4f/0x70
> [ 18.126326] [<ffffffff8108160e>] __blocking_notifier_call_chain+0x5e/0x90
> [ 18.134009] [<ffffffff81081656>] blocking_notifier_call_chain+0x16/0x20
> [ 18.141490] [<ffffffff810f0f00>] load_module+0x1b50/0x2660
> [ 18.147720] [<ffffffff810f1ade>] SyS_init_module+0xce/0x100
> [ 18.154045] [<ffffffff81587429>] system_call_fastpath+0x12/0x17
> [ 18.160748] ---[ end trace 9294429076a9c674 ]---
>
> Jump labels is not doing it right; fix this.
>
> Cc: Rusty Russell <ru...@rustcorp.com.au>
> Cc: Jason Baron <jba...@akamai.com>
> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Acked-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> ---
> kernel/jump_label.c | 21 +++++++++++++++++----
> 1 file changed, 17 insertions(+), 4 deletions(-)
>
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -280,6 +280,17 @@ void jump_label_apply_nops(struct module
> }
> }
>
> +static inline bool address_in_module(unsigned long addr, struct module *mod)
> +{
> + bool ret;
> +
> + preempt_disable();
> + ret = __module_address(addr) == mod;
> + preempt_enable();
> +
> + return ret;
> +}
> +
> static int jump_label_add_module(struct module *mod)
> {
> struct jump_entry *iter_start = mod->jump_entries;
> @@ -302,7 +313,7 @@ static int jump_label_add_module(struct
> continue;
>
> key = iterk;
> - if (__module_address(iter->key) == mod) {
> + if (address_in_module(iter->key, mod)) {
> /*
> * Set key->entries to iter, but preserve
> JUMP_LABEL_TRUE_BRANCH.
> */
> @@ -339,7 +350,7 @@ static void jump_label_del_module(struct
>
> key = (struct static_key *)(unsigned long)iter->key;
>
> - if (__module_address(iter->key) == mod)
> + if (address_in_module(iter->key, mod))
> continue;
>
> prev = &key->next;
> @@ -443,14 +454,16 @@ static void jump_label_update(struct sta
> {
> struct jump_entry *stop = __stop___jump_table;
> struct jump_entry *entry = jump_label_get_entries(key);
> -
> #ifdef CONFIG_MODULES
> - struct module *mod = __module_address((unsigned long)key);
> + struct module *mod;
>
> __jump_label_mod_update(key, enable);
>
> + preempt_disable();
> + mod = __module_address((unsigned long)key);
> if (mod)
> stop = mod->jump_entries + mod->num_jump_entries;
> + preempt_enable();
> #endif
> /* if there are no users, entry can be NULL */
> if (entry)
>
>
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