From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.org>
Cc: X86 ML <x86@kernel.org>, Masami Hiramatsu <mhiramat@kernel.org>,
Daniel Xu <dxu@dxuuu.xyz>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
kuba@kernel.org, mingo@redhat.com, ast@kernel.org,
tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com,
Josh Poimboeuf <jpoimboe@redhat.com>,
linux-ia64@vger.kernel.org,
Abhishek Sagar <sagar.abhishek@gmail.com>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>
Subject: [PATCH -tip v7 04/13] kprobes: Add kretprobe_find_ret_addr() for searching return address
Date: Thu, 27 May 2021 15:39:41 +0900 [thread overview]
Message-ID: <162209758165.436794.8504547064098766514.stgit@devnote2> (raw)
In-Reply-To: <162209754288.436794.3904335049560916855.stgit@devnote2>
Add kretprobe_find_ret_addr() for searching correct return address
from kretprobe instance list.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryik <andrii@kernel.org>
---
Changes in v6:
- Replace BUG_ON() with WARN_ON_ONCE() in __kretprobe_trampoline_handler().
Changes in v3:
- Remove generic stacktrace fixup. Instead, it should be solved in
each unwinder. This just provide the generic interface.
Changes in v2:
- Add is_kretprobe_trampoline() for checking address outside of
kretprobe_find_ret_addr()
- Remove unneeded addr from kretprobe_find_ret_addr()
- Rename fixup_kretprobe_tramp_addr() to fixup_kretprobe_trampoline()
---
include/linux/kprobes.h | 22 +++++++++++
kernel/kprobes.c | 91 ++++++++++++++++++++++++++++++++++-------------
2 files changed, 87 insertions(+), 26 deletions(-)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 65dadd4238a2..f530f82a046d 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -215,6 +215,14 @@ static nokprobe_inline void *kretprobe_trampoline_addr(void)
return dereference_function_descriptor(kretprobe_trampoline);
}
+static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
+{
+ return (void *)addr == kretprobe_trampoline_addr();
+}
+
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+ struct llist_node **cur);
+
/* If the trampoline handler called from a kprobe, use this version */
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
void *frame_pointer);
@@ -514,6 +522,20 @@ static inline bool is_kprobe_optinsn_slot(unsigned long addr)
}
#endif
+#if !defined(CONFIG_KRETPROBES)
+static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
+{
+ return false;
+}
+
+static nokprobe_inline
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+ struct llist_node **cur)
+{
+ return 0;
+}
+#endif
+
/* Returns true if kprobes handled the fault */
static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
unsigned int trap)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1d3087b59522..54e5b89aad67 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1858,45 +1858,69 @@ static struct notifier_block kprobe_exceptions_nb = {
#ifdef CONFIG_KRETPROBES
-unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
- void *frame_pointer)
+/* This assumes the tsk is current or the task which is not running. */
+static unsigned long __kretprobe_find_ret_addr(struct task_struct *tsk,
+ struct llist_node **cur)
{
- kprobe_opcode_t *correct_ret_addr = NULL;
struct kretprobe_instance *ri = NULL;
- struct llist_node *first, *node;
- struct kretprobe *rp;
+ struct llist_node *node = *cur;
+
+ if (!node)
+ node = tsk->kretprobe_instances.first;
+ else
+ node = node->next;
- /* Find all nodes for this frame. */
- first = node = current->kretprobe_instances.first;
while (node) {
ri = container_of(node, struct kretprobe_instance, llist);
-
- BUG_ON(ri->fp != frame_pointer);
-
if (ri->ret_addr != kretprobe_trampoline_addr()) {
- correct_ret_addr = ri->ret_addr;
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- goto found;
+ *cur = node;
+ return (unsigned long)ri->ret_addr;
}
-
node = node->next;
}
- pr_err("Oops! Kretprobe fails to find correct return address.\n");
- BUG_ON(1);
+ return 0;
+}
+NOKPROBE_SYMBOL(__kretprobe_find_ret_addr);
-found:
- /* Unlink all nodes for this frame. */
- current->kretprobe_instances.first = node->next;
- node->next = NULL;
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+ struct llist_node **cur)
+{
+ struct kretprobe_instance *ri = NULL;
+ unsigned long ret;
+
+ do {
+ ret = __kretprobe_find_ret_addr(tsk, cur);
+ if (!ret)
+ return ret;
+ ri = container_of(*cur, struct kretprobe_instance, llist);
+ } while (ri->fp != fp);
+
+ return ret;
+}
+NOKPROBE_SYMBOL(kretprobe_find_ret_addr);
- /* Run them.. */
+unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
+ void *frame_pointer)
+{
+ kprobe_opcode_t *correct_ret_addr = NULL;
+ struct kretprobe_instance *ri = NULL;
+ struct llist_node *first, *node = NULL;
+ struct kretprobe *rp;
+
+ /* Find correct address and all nodes for this frame. */
+ correct_ret_addr = (void *)__kretprobe_find_ret_addr(current, &node);
+ if (!correct_ret_addr) {
+ pr_err("Oops! Kretprobe fails to find correct return address.\n");
+ BUG_ON(1);
+ }
+
+ /* Run them. */
+ first = current->kretprobe_instances.first;
while (first) {
ri = container_of(first, struct kretprobe_instance, llist);
- first = first->next;
+
+ if (WARN_ON_ONCE(ri->fp != frame_pointer))
+ break;
rp = get_kretprobe(ri);
if (rp && rp->handler) {
@@ -1907,6 +1931,21 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
rp->handler(ri, regs);
__this_cpu_write(current_kprobe, prev);
}
+ if (first == node)
+ break;
+
+ first = first->next;
+ }
+
+ /* Unlink all nodes for this frame. */
+ first = current->kretprobe_instances.first;
+ current->kretprobe_instances.first = node->next;
+ node->next = NULL;
+
+ /* Recycle them. */
+ while (first) {
+ ri = container_of(first, struct kretprobe_instance, llist);
+ first = first->next;
recycle_rp_inst(ri);
}
next prev parent reply other threads:[~2021-05-27 6:39 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-27 6:39 [PATCH -tip v7 00/13] kprobes: Fix stacktrace with kretprobes on x86 Masami Hiramatsu
2021-05-27 6:39 ` [PATCH -tip v7 01/13] ia64: kprobes: Fix to pass correct trampoline address to the handler Masami Hiramatsu
2021-05-27 6:39 ` [PATCH -tip v7 02/13] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor() Masami Hiramatsu
2021-05-27 6:39 ` [PATCH -tip v7 03/13] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() Masami Hiramatsu
2021-06-14 15:46 ` Naveen N. Rao
2021-06-15 0:06 ` Masami Hiramatsu
2021-05-27 6:39 ` Masami Hiramatsu [this message]
2021-05-27 6:39 ` [PATCH -tip v7 05/13] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code Masami Hiramatsu
2021-05-27 6:40 ` [PATCH -tip v7 06/13] ARC: Add instruction_pointer_set() API Masami Hiramatsu
2021-05-27 6:40 ` [PATCH -tip v7 07/13] ia64: " Masami Hiramatsu
2021-05-27 6:40 ` [PATCH -tip v7 08/13] arm: kprobes: Make a space for regs->ARM_pc at kretprobe_trampoline Masami Hiramatsu
2021-05-27 6:40 ` [PATCH -tip v7 09/13] kprobes: Setup instruction pointer in __kretprobe_trampoline_handler Masami Hiramatsu
2021-06-17 4:39 ` Josh Poimboeuf
2021-06-17 4:40 ` Josh Poimboeuf
2021-06-17 14:40 ` Masami Hiramatsu
2021-06-17 15:02 ` Masami Hiramatsu
2021-06-17 17:45 ` Andrii Nakryiko
2021-06-17 18:21 ` Josh Poimboeuf
2021-06-17 18:31 ` Andrii Nakryiko
2021-06-17 19:26 ` Josh Poimboeuf
2021-06-17 19:46 ` Andrii Nakryiko
2021-06-18 0:33 ` Masami Hiramatsu
2021-06-18 1:03 ` Josh Poimboeuf
2021-06-17 23:58 ` Masami Hiramatsu
2021-06-18 0:58 ` Josh Poimboeuf
2021-05-27 6:40 ` [PATCH -tip v7 10/13] x86/kprobes: Push a fake return address at kretprobe_trampoline Masami Hiramatsu
2021-06-17 4:41 ` Josh Poimboeuf
2021-05-27 6:40 ` [PATCH -tip v7 11/13] x86/unwind: Recover kretprobe trampoline entry Masami Hiramatsu
2021-06-17 4:41 ` Josh Poimboeuf
2021-05-27 6:40 ` [PATCH -tip v7 12/13] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline Masami Hiramatsu
2021-05-27 6:41 ` [PATCH -tip v7 13/13] x86/kprobes: Fixup return address in generic trampoline handler Masami Hiramatsu
2021-05-27 16:41 ` [PATCH -tip v7 00/13] kprobes: Fix stacktrace with kretprobes on x86 Andrii Nakryiko
2021-06-10 3:40 ` Masami Hiramatsu
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