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-rw-r--r--arch/arm/kernel/kprobes.c6
-rw-r--r--arch/ia64/kernel/kprobes.c6
-rw-r--r--arch/powerpc/kernel/kprobes.c6
-rw-r--r--arch/s390/kernel/kprobes.c6
-rw-r--r--arch/sparc64/kernel/kprobes.c11
-rw-r--r--arch/x86/kernel/kprobes.c6
-rw-r--r--include/linux/kprobes.h7
-rw-r--r--kernel/kprobes.c127
8 files changed, 108 insertions, 67 deletions
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 5ee39e10c8d1..d28513f14d05 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -296,8 +296,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
@@ -337,7 +336,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
}
kretprobe_assert(ri, orig_ret_address, trampoline_address);
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
@@ -347,7 +346,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
return (void *)orig_ret_address;
}
-/* Called with kretprobe_lock held. */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 233434f4f88f..f07688da947c 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -429,8 +429,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
((struct fnptr *)kretprobe_trampoline)->ip;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
@@ -485,7 +484,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
kretprobe_assert(ri, orig_ret_address, trampoline_address);
reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
@@ -500,7 +499,6 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
return 1;
}
-/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 4ba2af125450..de79915452c8 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -144,7 +144,6 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
kcb->kprobe_saved_msr = regs->msr;
}
-/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
@@ -312,8 +311,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
@@ -352,7 +350,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
regs->nip = orig_ret_address;
reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 288ad490a6dd..4f82e5b5f879 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -270,7 +270,6 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
__ctl_store(kcb->kprobe_saved_ctl, 9, 11);
}
-/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
@@ -377,8 +376,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
@@ -417,7 +415,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE;
reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index f43b5d755354..201a6e547e4a 100644
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -478,9 +478,9 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
return 0;
}
-/* Called with kretprobe_lock held. The value stored in the return
- * address register is actually 2 instructions before where the
- * callee will return to. Sequences usually look something like this
+/* The value stored in the return address register is actually 2
+ * instructions before where the callee will return to.
+ * Sequences usually look something like this
*
* call some_function <--- return register points here
* nop <--- call delay slot
@@ -512,8 +512,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
@@ -553,7 +552,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
regs->tnpc = orig_ret_address + 4;
reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 43c019f85f0d..6c27679ec6aa 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -431,7 +431,6 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
regs->ip = (unsigned long)p->ainsn.insn;
}
-/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
@@ -682,8 +681,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/* fixup registers */
#ifdef CONFIG_X86_64
regs->cs = __KERNEL_CS;
@@ -732,7 +730,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
kretprobe_assert(ri, orig_ret_address, trampoline_address);
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 04a3556bdea6..0be7795655fa 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -157,11 +157,10 @@ struct kretprobe {
int nmissed;
size_t data_size;
struct hlist_head free_instances;
- struct hlist_head used_instances;
+ spinlock_t lock;
};
struct kretprobe_instance {
- struct hlist_node uflist; /* either on free list or used list */
struct hlist_node hlist;
struct kretprobe *rp;
kprobe_opcode_t *ret_addr;
@@ -201,7 +200,6 @@ static inline int init_test_probes(void)
}
#endif /* CONFIG_KPROBES_SANITY_TEST */
-extern spinlock_t kretprobe_lock;
extern struct mutex kprobe_mutex;
extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
@@ -214,6 +212,9 @@ extern void kprobes_inc_nmissed_count(struct kprobe *p);
/* Get the kprobe at this addr (if any) - called with preemption disabled */
struct kprobe *get_kprobe(void *addr);
+void kretprobe_hash_lock(struct task_struct *tsk,
+ struct hlist_head **head, unsigned long *flags);
+void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
/* kprobe_running() will just return the current_kprobe on this CPU */
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1485ca8d0e00..cb0b3bde3617 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -62,6 +62,7 @@
addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
#endif
+static int kprobes_initialized;
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
@@ -69,8 +70,15 @@ static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
static bool kprobe_enabled;
DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
-DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
+static struct {
+ spinlock_t lock ____cacheline_aligned;
+} kretprobe_table_locks[KPROBE_TABLE_SIZE];
+
+static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
+{
+ return &(kretprobe_table_locks[hash].lock);
+}
/*
* Normally, functions that we'd want to prohibit kprobes in, are marked
@@ -368,26 +376,53 @@ void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
return;
}
-/* Called with kretprobe_lock held */
void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
struct hlist_head *head)
{
+ struct kretprobe *rp = ri->rp;
+
/* remove rp inst off the rprobe_inst_table */
hlist_del(&ri->hlist);
- if (ri->rp) {
- /* remove rp inst off the used list */
- hlist_del(&ri->uflist);
- /* put rp inst back onto the free list */
- INIT_HLIST_NODE(&ri->uflist);
- hlist_add_head(&ri->uflist, &ri->rp->free_instances);
+ INIT_HLIST_NODE(&ri->hlist);
+ if (likely(rp)) {
+ spin_lock(&rp->lock);
+ hlist_add_head(&ri->hlist, &rp->free_instances);
+ spin_unlock(&rp->lock);
} else
/* Unregistering */
hlist_add_head(&ri->hlist, head);
}
-struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
+void kretprobe_hash_lock(struct task_struct *tsk,
+ struct hlist_head **head, unsigned long *flags)
+{
+ unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
+ spinlock_t *hlist_lock;
+
+ *head = &kretprobe_inst_table[hash];
+ hlist_lock = kretprobe_table_lock_ptr(hash);
+ spin_lock_irqsave(hlist_lock, *flags);
+}
+
+void kretprobe_table_lock(unsigned long hash, unsigned long *flags)
{
- return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
+ spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
+ spin_lock_irqsave(hlist_lock, *flags);
+}
+
+void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags)
+{
+ unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
+ spinlock_t *hlist_lock;
+
+ hlist_lock = kretprobe_table_lock_ptr(hash);
+ spin_unlock_irqrestore(hlist_lock, *flags);
+}
+
+void kretprobe_table_unlock(unsigned long hash, unsigned long *flags)
+{
+ spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
+ spin_unlock_irqrestore(hlist_lock, *flags);
}
/*
@@ -401,17 +436,21 @@ void __kprobes kprobe_flush_task(struct task_struct *tk)
struct kretprobe_instance *ri;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
- unsigned long flags = 0;
+ unsigned long hash, flags = 0;
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(tk);
+ if (unlikely(!kprobes_initialized))
+ /* Early boot. kretprobe_table_locks not yet initialized. */
+ return;
+
+ hash = hash_ptr(tk, KPROBE_HASH_BITS);
+ head = &kretprobe_inst_table[hash];
+ kretprobe_table_lock(hash, &flags);
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
if (ri->task == tk)
recycle_rp_inst(ri, &empty_rp);
}
- spin_unlock_irqrestore(&kretprobe_lock, flags);
-
+ kretprobe_table_unlock(hash, &flags);
+ INIT_HLIST_HEAD(&empty_rp);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
@@ -423,24 +462,29 @@ static inline void free_rp_inst(struct kretprobe *rp)
struct kretprobe_instance *ri;
struct hlist_node *pos, *next;
- hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) {
- hlist_del(&ri->uflist);
+ hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
+ hlist_del(&ri->hlist);
kfree(ri);
}
}
static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
{
- unsigned long flags;
+ unsigned long flags, hash;
struct kretprobe_instance *ri;
struct hlist_node *pos, *next;
+ struct hlist_head *head;
+
/* No race here */
- spin_lock_irqsave(&kretprobe_lock, flags);
- hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
- ri->rp = NULL;
- hlist_del(&ri->uflist);
+ for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
+ kretprobe_table_lock(hash, &flags);
+ head = &kretprobe_inst_table[hash];
+ hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
+ if (ri->rp == rp)
+ ri->rp = NULL;
+ }
+ kretprobe_table_unlock(hash, &flags);
}
- spin_unlock_irqrestore(&kretprobe_lock, flags);
free_rp_inst(rp);
}
@@ -831,32 +875,37 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
struct pt_regs *regs)
{
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
- unsigned long flags = 0;
+ unsigned long hash, flags = 0;
+ struct kretprobe_instance *ri;
/*TODO: consider to only swap the RA after the last pre_handler fired */
- spin_lock_irqsave(&kretprobe_lock, flags);
+ hash = hash_ptr(current, KPROBE_HASH_BITS);
+ spin_lock_irqsave(&rp->lock, flags);
if (!hlist_empty(&rp->free_instances)) {
- struct kretprobe_instance *ri;
-
ri = hlist_entry(rp->free_instances.first,
- struct kretprobe_instance, uflist);
+ struct kretprobe_instance, hlist);
+ hlist_del(&ri->hlist);
+ spin_unlock_irqrestore(&rp->lock, flags);
+
ri->rp = rp;
ri->task = current;
if (rp->entry_handler && rp->entry_handler(ri, regs)) {
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ spin_unlock_irqrestore(&rp->lock, flags);
return 0;
}
arch_prepare_kretprobe(ri, regs);
/* XXX(hch): why is there no hlist_move_head? */
- hlist_del(&ri->uflist);
- hlist_add_head(&ri->uflist, &ri->rp->used_instances);
- hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task));
- } else
+ INIT_HLIST_NODE(&ri->hlist);
+ kretprobe_table_lock(hash, &flags);
+ hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
+ kretprobe_table_unlock(hash, &flags);
+ } else {
rp->nmissed++;
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ spin_unlock_irqrestore(&rp->lock, flags);
+ }
return 0;
}
@@ -892,7 +941,7 @@ static int __kprobes __register_kretprobe(struct kretprobe *rp,
rp->maxactive = NR_CPUS;
#endif
}
- INIT_HLIST_HEAD(&rp->used_instances);
+ spin_lock_init(&rp->lock);
INIT_HLIST_HEAD(&rp->free_instances);
for (i = 0; i < rp->maxactive; i++) {
inst = kmalloc(sizeof(struct kretprobe_instance) +
@@ -901,8 +950,8 @@ static int __kprobes __register_kretprobe(struct kretprobe *rp,
free_rp_inst(rp);
return -ENOMEM;
}
- INIT_HLIST_NODE(&inst->uflist);
- hlist_add_head(&inst->uflist, &rp->free_instances);
+ INIT_HLIST_NODE(&inst->hlist);
+ hlist_add_head(&inst->hlist, &rp->free_instances);
}
rp->nmissed = 0;
@@ -1009,6 +1058,7 @@ static int __init init_kprobes(void)
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
INIT_HLIST_HEAD(&kprobe_table[i]);
INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
+ spin_lock_init(&(kretprobe_table_locks[i].lock));
}
/*
@@ -1050,6 +1100,7 @@ static int __init init_kprobes(void)
err = arch_init_kprobes();
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
+ kprobes_initialized = (err == 0);
if (!err)
init_test_probes();
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.