linux-kernel - [tip: perf/core] uprobes: Add do_ref_ctr argument to uprobe

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Message-ID: <175611750173.1420.10521159088686098877.tip-bot2@tip-bot2>
Date: Mon, 25 Aug 2025 10:25:01 -0000
From: "tip-bot2 for Jiri Olsa" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Jiri Olsa <jolsa@...nel.org>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 "Masami Hiramatsu (Google)" <mhiramat@...nel.org>,
 Andrii Nakryiko <andrii@...nel.org>, Oleg Nesterov <oleg@...hat.com>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject:
 [tip: perf/core] uprobes: Add do_ref_ctr argument to uprobe_write function

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     18a111256a0b4fedfe47101f084441a84d7e357a
Gitweb:        https://git.kernel.org/tip/18a111256a0b4fedfe47101f084441a84d7e357a
Author:        Jiri Olsa <jolsa@...nel.org>
AuthorDate:    Sun, 20 Jul 2025 13:21:17 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Thu, 21 Aug 2025 20:09:20 +02:00

uprobes: Add do_ref_ctr argument to uprobe_write function

Making update_ref_ctr call in uprobe_write conditional based
on do_ref_ctr argument. This way we can use uprobe_write for
instruction update without doing ref_ctr_offset update.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Acked-by: Andrii Nakryiko <andrii@...nel.org>
Acked-by: Oleg Nesterov <oleg@...hat.com>
Link: https://lore.kernel.org/r/20250720112133.244369-8-jolsa@kernel.org
---
 include/linux/uprobes.h | 2 +-
 kernel/events/uprobes.c | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 518b267..5080619 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -200,7 +200,7 @@ extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
 extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t,
 			       bool is_register);
 extern int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, const unsigned long opcode_vaddr,
-			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register);
+			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr);
 extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
 extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);
 extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 955e5ed..da2b3d0 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -491,12 +491,12 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 		bool is_register)
 {
 	return uprobe_write(auprobe, vma, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE,
-			    verify_opcode, is_register);
+			    verify_opcode, is_register, true /* do_update_ref_ctr */);
 }
 
 int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 		 const unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes,
-		 uprobe_write_verify_t verify, bool is_register)
+		 uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr)
 {
 	const unsigned long vaddr = insn_vaddr & PAGE_MASK;
 	struct mm_struct *mm = vma->vm_mm;
@@ -537,7 +537,7 @@ retry:
 	}
 
 	/* We are going to replace instruction, update ref_ctr. */
-	if (!ref_ctr_updated && uprobe->ref_ctr_offset) {
+	if (do_update_ref_ctr && !ref_ctr_updated && uprobe->ref_ctr_offset) {
 		ret = update_ref_ctr(uprobe, mm, is_register ? 1 : -1);
 		if (ret) {
 			folio_put(folio);
@@ -589,7 +589,7 @@ retry:
 
 out:
 	/* Revert back reference counter if instruction update failed. */
-	if (ret < 0 && ref_ctr_updated)
+	if (do_update_ref_ctr && ret < 0 && ref_ctr_updated)
 		update_ref_ctr(uprobe, mm, is_register ? -1 : 1);
 
 	/* try collapse pmd for compound page */