Revision 6fd4b15603124c1b56e03db29b41ec39d8a077b9 authored by Steve Cornelius on 15 June 2015, 23:52:56 UTC, committed by Herbert Xu on 16 June 2015, 06:20:38 UTC
Multiple function in asynchronous hashing use a saved-state block, a.k.a. struct caam_hash_state, which holds a stash of information between requests (init/update/final). Certain values in this state block are loaded for processing using an inline-if, and when this is done, the potential for uninitialized data can pose conflicts. Therefore, this patch improves initialization of state data to prevent false assignments using uninitialized data in the state block. This patch addresses the following traceback, originating in ahash_final_ctx(), although a problem like this could certainly exhibit other symptoms: kernel BUG at arch/arm/mm/dma-mapping.c:465! Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = 80004000 [00000000] *pgd=00000000 Internal error: Oops: 805 [#1] PREEMPT SMP Modules linked in: CPU: 0 Not tainted (3.0.15-01752-gdd441b9-dirty #40) PC is at __bug+0x1c/0x28 LR is at __bug+0x18/0x28 pc : [<80043240>] lr : [<8004323c>] psr: 60000013 sp : e423fd98 ip : 60000013 fp : 0000001c r10: e4191b84 r9 : 00000020 r8 : 00000009 r7 : 88005038 r6 : 00000001 r5 : 2d676572 r4 : e4191a60 r3 : 00000000 r2 : 00000001 r1 : 60000093 r0 : 00000033 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c53c7d Table: 1000404a DAC: 00000015 Process cryptomgr_test (pid: 1306, stack limit = 0xe423e2f0) Stack: (0xe423fd98 to 0xe4240000) fd80: 11807fd1 80048544 fda0: 88005000 e4191a00 e5178040 8039dda0 00000000 00000014 2d676572 e4191008 fdc0: 88005018 e4191a60 00100100 e4191a00 00000000 8039ce0c e423fea8 00000007 fde0: e4191a00 e4227000 e5178000 8039ce18 e419183c 80203808 80a94a44 00000006 fe00: 00000000 80207180 00000000 00000006 e423ff08 00000000 00000007 e5178000 fe20: e41918a4 80a949b4 8c4844e2 00000000 00000049 74227000 8c4844e2 00000e90 fe40: 0000000e 74227e90 ffff8c58 80ac29e0 e423fed4 8006a350 8c81625c e423ff5c fe60: 00008576 e4002500 00000003 00030010 e4002500 00000003 e5180000 e4002500 fe80: e5178000 800e6d24 007fffff 00000000 00000010 e4001280 e4002500 60000013 fea0: 000000d0 804df078 00000000 00000000 00000000 00000000 00000000 00000000 fec0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 fee0: 00000000 00000000 e4227000 e4226000 e4753000 e4752000 e40a5000 e40a4000 ff00: e41e7000 e41e6000 00000000 00000000 00000000 e423ff14 e423ff14 00000000 ff20: 00000400 804f9080 e5178000 e4db0b40 00000000 e4db0b80 0000047c 00000400 ff40: 00000000 8020758c 00000400 ffffffff 0000008a 00000000 e4db0b40 80206e00 ff60: e4049dbc 00000000 00000000 00000003 e423ffa4 80062978 e41a8bfc 00000000 ff80: 00000000 e4049db4 00000013 e4049db0 00000013 00000000 00000000 00000000 ffa0: e4db0b40 e4db0b40 80204cbc 00000013 00000000 00000000 00000000 80204cfc ffc0: e4049da0 80089544 80040a40 00000000 e4db0b40 00000000 00000000 00000000 ffe0: e423ffe0 e423ffe0 e4049da0 800894c4 80040a40 80040a40 00000000 00000000 [<80043240>] (__bug+0x1c/0x28) from [<80048544>] (___dma_single_dev_to_cpu+0x84) [<80048544>] (___dma_single_dev_to_cpu+0x84/0x94) from [<8039dda0>] (ahash_fina) [<8039dda0>] (ahash_final_ctx+0x180/0x428) from [<8039ce18>] (ahash_final+0xc/0) [<8039ce18>] (ahash_final+0xc/0x10) from [<80203808>] (crypto_ahash_op+0x28/0xc) [<80203808>] (crypto_ahash_op+0x28/0xc0) from [<80207180>] (test_hash+0x214/0x5) [<80207180>] (test_hash+0x214/0x5b8) from [<8020758c>] (alg_test_hash+0x68/0x8c) [<8020758c>] (alg_test_hash+0x68/0x8c) from [<80206e00>] (alg_test+0x7c/0x1b8) [<80206e00>] (alg_test+0x7c/0x1b8) from [<80204cfc>] (cryptomgr_test+0x40/0x48) [<80204cfc>] (cryptomgr_test+0x40/0x48) from [<80089544>] (kthread+0x80/0x88) [<80089544>] (kthread+0x80/0x88) from [<80040a40>] (kernel_thread_exit+0x0/0x8) Code: e59f0010 e1a01003 eb126a8d e3a03000 (e5833000) ---[ end trace d52a403a1d1eaa86 ]--- Cc: stable@vger.kernel.org Signed-off-by: Steve Cornelius <steve.cornelius@freescale.com> Signed-off-by: Victoria Milhoan <vicki.milhoan@freescale.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
1 parent f858c7b
tracepoint.c
/*
* Copyright (C) 2008-2014 Mathieu Desnoyers
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/jhash.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/tracepoint.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/static_key.h>
extern struct tracepoint * const __start___tracepoints_ptrs[];
extern struct tracepoint * const __stop___tracepoints_ptrs[];
/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;
#ifdef CONFIG_MODULES
/*
* Tracepoint module list mutex protects the local module list.
*/
static DEFINE_MUTEX(tracepoint_module_list_mutex);
/* Local list of struct tp_module */
static LIST_HEAD(tracepoint_module_list);
#endif /* CONFIG_MODULES */
/*
* tracepoints_mutex protects the builtin and module tracepoints.
* tracepoints_mutex nests inside tracepoint_module_list_mutex.
*/
static DEFINE_MUTEX(tracepoints_mutex);
/*
* Note about RCU :
* It is used to delay the free of multiple probes array until a quiescent
* state is reached.
*/
struct tp_probes {
struct rcu_head rcu;
struct tracepoint_func probes[0];
};
static inline void *allocate_probes(int count)
{
struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func)
+ sizeof(struct tp_probes), GFP_KERNEL);
return p == NULL ? NULL : p->probes;
}
static void rcu_free_old_probes(struct rcu_head *head)
{
kfree(container_of(head, struct tp_probes, rcu));
}
static inline void release_probes(struct tracepoint_func *old)
{
if (old) {
struct tp_probes *tp_probes = container_of(old,
struct tp_probes, probes[0]);
call_rcu_sched(&tp_probes->rcu, rcu_free_old_probes);
}
}
static void debug_print_probes(struct tracepoint_func *funcs)
{
int i;
if (!tracepoint_debug || !funcs)
return;
for (i = 0; funcs[i].func; i++)
printk(KERN_DEBUG "Probe %d : %p\n", i, funcs[i].func);
}
static struct tracepoint_func *func_add(struct tracepoint_func **funcs,
struct tracepoint_func *tp_func)
{
int nr_probes = 0;
struct tracepoint_func *old, *new;
if (WARN_ON(!tp_func->func))
return ERR_PTR(-EINVAL);
debug_print_probes(*funcs);
old = *funcs;
if (old) {
/* (N -> N+1), (N != 0, 1) probes */
for (nr_probes = 0; old[nr_probes].func; nr_probes++)
if (old[nr_probes].func == tp_func->func &&
old[nr_probes].data == tp_func->data)
return ERR_PTR(-EEXIST);
}
/* + 2 : one for new probe, one for NULL func */
new = allocate_probes(nr_probes + 2);
if (new == NULL)
return ERR_PTR(-ENOMEM);
if (old)
memcpy(new, old, nr_probes * sizeof(struct tracepoint_func));
new[nr_probes] = *tp_func;
new[nr_probes + 1].func = NULL;
*funcs = new;
debug_print_probes(*funcs);
return old;
}
static void *func_remove(struct tracepoint_func **funcs,
struct tracepoint_func *tp_func)
{
int nr_probes = 0, nr_del = 0, i;
struct tracepoint_func *old, *new;
old = *funcs;
if (!old)
return ERR_PTR(-ENOENT);
debug_print_probes(*funcs);
/* (N -> M), (N > 1, M >= 0) probes */
if (tp_func->func) {
for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
if (old[nr_probes].func == tp_func->func &&
old[nr_probes].data == tp_func->data)
nr_del++;
}
}
/*
* If probe is NULL, then nr_probes = nr_del = 0, and then the
* entire entry will be removed.
*/
if (nr_probes - nr_del == 0) {
/* N -> 0, (N > 1) */
*funcs = NULL;
debug_print_probes(*funcs);
return old;
} else {
int j = 0;
/* N -> M, (N > 1, M > 0) */
/* + 1 for NULL */
new = allocate_probes(nr_probes - nr_del + 1);
if (new == NULL)
return ERR_PTR(-ENOMEM);
for (i = 0; old[i].func; i++)
if (old[i].func != tp_func->func
|| old[i].data != tp_func->data)
new[j++] = old[i];
new[nr_probes - nr_del].func = NULL;
*funcs = new;
}
debug_print_probes(*funcs);
return old;
}
/*
* Add the probe function to a tracepoint.
*/
static int tracepoint_add_func(struct tracepoint *tp,
struct tracepoint_func *func)
{
struct tracepoint_func *old, *tp_funcs;
if (tp->regfunc && !static_key_enabled(&tp->key))
tp->regfunc();
tp_funcs = rcu_dereference_protected(tp->funcs,
lockdep_is_held(&tracepoints_mutex));
old = func_add(&tp_funcs, func);
if (IS_ERR(old)) {
WARN_ON_ONCE(1);
return PTR_ERR(old);
}
/*
* rcu_assign_pointer has a smp_wmb() which makes sure that the new
* probe callbacks array is consistent before setting a pointer to it.
* This array is referenced by __DO_TRACE from
* include/linux/tracepoints.h. A matching smp_read_barrier_depends()
* is used.
*/
rcu_assign_pointer(tp->funcs, tp_funcs);
if (!static_key_enabled(&tp->key))
static_key_slow_inc(&tp->key);
release_probes(old);
return 0;
}
/*
* Remove a probe function from a tracepoint.
* Note: only waiting an RCU period after setting elem->call to the empty
* function insures that the original callback is not used anymore. This insured
* by preempt_disable around the call site.
*/
static int tracepoint_remove_func(struct tracepoint *tp,
struct tracepoint_func *func)
{
struct tracepoint_func *old, *tp_funcs;
tp_funcs = rcu_dereference_protected(tp->funcs,
lockdep_is_held(&tracepoints_mutex));
old = func_remove(&tp_funcs, func);
if (IS_ERR(old)) {
WARN_ON_ONCE(1);
return PTR_ERR(old);
}
if (!tp_funcs) {
/* Removed last function */
if (tp->unregfunc && static_key_enabled(&tp->key))
tp->unregfunc();
if (static_key_enabled(&tp->key))
static_key_slow_dec(&tp->key);
}
rcu_assign_pointer(tp->funcs, tp_funcs);
release_probes(old);
return 0;
}
/**
* tracepoint_probe_register - Connect a probe to a tracepoint
* @tp: tracepoint
* @probe: probe handler
* @data: tracepoint data
*
* Returns 0 if ok, error value on error.
* Note: if @tp is within a module, the caller is responsible for
* unregistering the probe before the module is gone. This can be
* performed either with a tracepoint module going notifier, or from
* within module exit functions.
*/
int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data)
{
struct tracepoint_func tp_func;
int ret;
mutex_lock(&tracepoints_mutex);
tp_func.func = probe;
tp_func.data = data;
ret = tracepoint_add_func(tp, &tp_func);
mutex_unlock(&tracepoints_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
/**
* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
* @tp: tracepoint
* @probe: probe function pointer
* @data: tracepoint data
*
* Returns 0 if ok, error value on error.
*/
int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
{
struct tracepoint_func tp_func;
int ret;
mutex_lock(&tracepoints_mutex);
tp_func.func = probe;
tp_func.data = data;
ret = tracepoint_remove_func(tp, &tp_func);
mutex_unlock(&tracepoints_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
#ifdef CONFIG_MODULES
bool trace_module_has_bad_taint(struct module *mod)
{
return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
(1 << TAINT_UNSIGNED_MODULE));
}
static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
/**
* register_tracepoint_notifier - register tracepoint coming/going notifier
* @nb: notifier block
*
* Notifiers registered with this function are called on module
* coming/going with the tracepoint_module_list_mutex held.
* The notifier block callback should expect a "struct tp_module" data
* pointer.
*/
int register_tracepoint_module_notifier(struct notifier_block *nb)
{
struct tp_module *tp_mod;
int ret;
mutex_lock(&tracepoint_module_list_mutex);
ret = blocking_notifier_chain_register(&tracepoint_notify_list, nb);
if (ret)
goto end;
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
(void) nb->notifier_call(nb, MODULE_STATE_COMING, tp_mod);
end:
mutex_unlock(&tracepoint_module_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(register_tracepoint_module_notifier);
/**
* unregister_tracepoint_notifier - unregister tracepoint coming/going notifier
* @nb: notifier block
*
* The notifier block callback should expect a "struct tp_module" data
* pointer.
*/
int unregister_tracepoint_module_notifier(struct notifier_block *nb)
{
struct tp_module *tp_mod;
int ret;
mutex_lock(&tracepoint_module_list_mutex);
ret = blocking_notifier_chain_unregister(&tracepoint_notify_list, nb);
if (ret)
goto end;
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
(void) nb->notifier_call(nb, MODULE_STATE_GOING, tp_mod);
end:
mutex_unlock(&tracepoint_module_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
/*
* Ensure the tracer unregistered the module's probes before the module
* teardown is performed. Prevents leaks of probe and data pointers.
*/
static void tp_module_going_check_quiescent(struct tracepoint * const *begin,
struct tracepoint * const *end)
{
struct tracepoint * const *iter;
if (!begin)
return;
for (iter = begin; iter < end; iter++)
WARN_ON_ONCE((*iter)->funcs);
}
static int tracepoint_module_coming(struct module *mod)
{
struct tp_module *tp_mod;
int ret = 0;
if (!mod->num_tracepoints)
return 0;
/*
* We skip modules that taint the kernel, especially those with different
* module headers (for forced load), to make sure we don't cause a crash.
* Staging, out-of-tree, and unsigned GPL modules are fine.
*/
if (trace_module_has_bad_taint(mod))
return 0;
mutex_lock(&tracepoint_module_list_mutex);
tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
if (!tp_mod) {
ret = -ENOMEM;
goto end;
}
tp_mod->mod = mod;
list_add_tail(&tp_mod->list, &tracepoint_module_list);
blocking_notifier_call_chain(&tracepoint_notify_list,
MODULE_STATE_COMING, tp_mod);
end:
mutex_unlock(&tracepoint_module_list_mutex);
return ret;
}
static void tracepoint_module_going(struct module *mod)
{
struct tp_module *tp_mod;
if (!mod->num_tracepoints)
return;
mutex_lock(&tracepoint_module_list_mutex);
list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
if (tp_mod->mod == mod) {
blocking_notifier_call_chain(&tracepoint_notify_list,
MODULE_STATE_GOING, tp_mod);
list_del(&tp_mod->list);
kfree(tp_mod);
/*
* Called the going notifier before checking for
* quiescence.
*/
tp_module_going_check_quiescent(mod->tracepoints_ptrs,
mod->tracepoints_ptrs + mod->num_tracepoints);
break;
}
}
/*
* In the case of modules that were tainted at "coming", we'll simply
* walk through the list without finding it. We cannot use the "tainted"
* flag on "going", in case a module taints the kernel only after being
* loaded.
*/
mutex_unlock(&tracepoint_module_list_mutex);
}
static int tracepoint_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
int ret = 0;
switch (val) {
case MODULE_STATE_COMING:
ret = tracepoint_module_coming(mod);
break;
case MODULE_STATE_LIVE:
break;
case MODULE_STATE_GOING:
tracepoint_module_going(mod);
break;
case MODULE_STATE_UNFORMED:
break;
}
return ret;
}
static struct notifier_block tracepoint_module_nb = {
.notifier_call = tracepoint_module_notify,
.priority = 0,
};
static __init int init_tracepoints(void)
{
int ret;
ret = register_module_notifier(&tracepoint_module_nb);
if (ret)
pr_warning("Failed to register tracepoint module enter notifier\n");
return ret;
}
__initcall(init_tracepoints);
#endif /* CONFIG_MODULES */
static void for_each_tracepoint_range(struct tracepoint * const *begin,
struct tracepoint * const *end,
void (*fct)(struct tracepoint *tp, void *priv),
void *priv)
{
struct tracepoint * const *iter;
if (!begin)
return;
for (iter = begin; iter < end; iter++)
fct(*iter, priv);
}
/**
* for_each_kernel_tracepoint - iteration on all kernel tracepoints
* @fct: callback
* @priv: private data
*/
void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
void *priv)
{
for_each_tracepoint_range(__start___tracepoints_ptrs,
__stop___tracepoints_ptrs, fct, priv);
}
EXPORT_SYMBOL_GPL(for_each_kernel_tracepoint);
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
static int sys_tracepoint_refcount;
void syscall_regfunc(void)
{
struct task_struct *p, *t;
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}
sys_tracepoint_refcount++;
}
void syscall_unregfunc(void)
{
struct task_struct *p, *t;
sys_tracepoint_refcount--;
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}
}
#endif
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