From: Masami Hiramatsu <mhiramat@kernel.org>
To: linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>
Cc: Eddy Wu <Eddy_Wu@trendmicro.com>,
x86@kernel.org, "David S . Miller" <davem@davemloft.net>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
linux-arch@vger.kernel.org, guoren@kernel.org
Subject: [PATCH v3 02/16] x86/kprobes: Use generic kretprobe trampoline handler
Date: Fri, 28 Aug 2020 01:38:52 +0900 [thread overview]
Message-ID: <159854633260.736475.6150536825710984256.stgit@devnote2> (raw)
In-Reply-To: <159854631442.736475.5062989489155389472.stgit@devnote2>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/x86/kernel/kprobes/core.c | 109 +---------------------------------------
1 file changed, 4 insertions(+), 105 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index fdadc37d72af..7c6473a12cee 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -767,124 +767,23 @@ asm(
NOKPROBE_SYMBOL(kretprobe_trampoline);
STACK_FRAME_NON_STANDARD(kretprobe_trampoline);
+
/*
* Called from kretprobe_trampoline
*/
__used __visible void *trampoline_handler(struct pt_regs *regs)
{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
- kprobe_opcode_t *correct_ret_addr = NULL;
- void *frame_pointer;
- bool skipped = false;
-
- /*
- * Set a dummy kprobe for avoiding kretprobe recursion.
- * Since kretprobe never run in kprobe handler, kprobe must not
- * be running at this point.
- */
- kprobe_busy_begin();
-
- INIT_HLIST_HEAD(&empty_rp);
- kretprobe_hash_lock(current, &head, &flags);
/* fixup registers */
regs->cs = __KERNEL_CS;
#ifdef CONFIG_X86_32
regs->cs |= get_kernel_rpl();
regs->gs = 0;
#endif
- /* We use pt_regs->sp for return address holder. */
- frame_pointer = ®s->sp;
- regs->ip = trampoline_address;
+ regs->ip = (unsigned long)&kretprobe_trampoline;
regs->orig_ax = ~0UL;
- /*
- * It is possible to have multiple instances associated with a given
- * task either because multiple functions in the call path have
- * return probes installed on them, and/or more than one
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always pushed into the head of the list
- * - when multiple return probes are registered for the same
- * function, the (chronologically) first instance's ret_addr
- * will be the real return address, and all the rest will
- * point to kretprobe_trampoline.
- */
- hlist_for_each_entry(ri, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
- /*
- * Return probes must be pushed on this hash list correct
- * order (same as return order) so that it can be popped
- * correctly. However, if we find it is pushed it incorrect
- * order, this means we find a function which should not be
- * probed, because the wrong order entry is pushed on the
- * path of processing other kretprobe itself.
- */
- if (ri->fp != frame_pointer) {
- if (!skipped)
- pr_warn("kretprobe is stacked incorrectly. Trying to fixup.\n");
- skipped = true;
- continue;
- }
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- if (skipped)
- pr_warn("%ps must be blacklisted because of incorrect kretprobe order\n",
- ri->rp->kp.addr);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
- correct_ret_addr = ri->ret_addr;
- hlist_for_each_entry_safe(ri, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
- if (ri->fp != frame_pointer)
- continue;
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- if (ri->rp && ri->rp->handler) {
- __this_cpu_write(current_kprobe, &ri->rp->kp);
- ri->ret_addr = correct_ret_addr;
- ri->rp->handler(ri, regs);
- __this_cpu_write(current_kprobe, &kprobe_busy);
- }
-
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_hash_unlock(current, &flags);
-
- kprobe_busy_end();
-
- hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- return (void *)orig_ret_address;
+ return (void *)kretprobe_trampoline_handler(regs,
+ (unsigned long)&kretprobe_trampoline, ®s->sp);
}
NOKPROBE_SYMBOL(trampoline_handler);
next prev parent reply other threads:[~2020-08-27 16:39 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 16:38 [PATCH v3 00/16] kprobes: Unify kretprobe trampoline handlers Masami Hiramatsu
2020-08-27 16:38 ` [PATCH v3 01/16] kprobes: Add generic kretprobe trampoline handler Masami Hiramatsu
2020-08-28 1:57 ` Masami Hiramatsu
2020-08-27 16:38 ` Masami Hiramatsu [this message]
2020-08-27 16:39 ` [PATCH v3 03/16] arm: kprobes: Use " Masami Hiramatsu
2020-08-27 16:39 ` [PATCH v3 04/16] arm64: " Masami Hiramatsu
2020-08-27 16:39 ` [PATCH v3 05/16] arc: " Masami Hiramatsu
2020-08-27 16:39 ` [PATCH v3 06/16] csky: " Masami Hiramatsu
2020-08-28 12:34 ` Guo Ren
2020-08-29 9:31 ` Masami Hiramatsu
2020-08-27 16:39 ` [PATCH v3 07/16] ia64: " Masami Hiramatsu
2020-08-27 16:39 ` [PATCH v3 08/16] mips: " Masami Hiramatsu
2020-08-27 16:39 ` [PATCH v3 09/16] parisc: " Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 10/16] powerpc: " Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 11/16] s390: " Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 12/16] sh: " Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 13/16] sparc: " Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 14/16] kprobes: Remove NMI context check Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 15/16] kprobes: Free kretprobe_instance with rcu callback Masami Hiramatsu
2020-08-27 16:40 ` [PATCH v3 16/16] kprobes: Make local used functions static Masami Hiramatsu
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