diff mbox

[V3,27/32] arm: Prevent hotplug rwsem recursion

Message ID 20170524081549.275871311@linutronix.de (mailing list archive)
State New, archived
Headers show

Commit Message

Thomas Gleixner May 24, 2017, 8:15 a.m. UTC
The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.

Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@armlinux.org.uk>
---
 arch/arm/kernel/patch.c        |    2 +-
 arch/arm/probes/kprobes/core.c |    3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)
diff mbox

Patch

--- a/arch/arm/kernel/patch.c
+++ b/arch/arm/kernel/patch.c
@@ -124,5 +124,5 @@  void __kprobes patch_text(void *addr, un
 		.insn = insn,
 	};
 
-	stop_machine(patch_text_stop_machine, &patch, NULL);
+	stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
 }
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -182,7 +182,8 @@  void __kprobes kprobes_remove_breakpoint
 		.addr = addr,
 		.insn = insn,
 	};
-	stop_machine(__kprobes_remove_breakpoint, &p, cpu_online_mask);
+	stop_machine_cpuslocked(__kprobes_remove_breakpoint, &p,
+				cpu_online_mask);
 }
 
 void __kprobes arch_disarm_kprobe(struct kprobe *p)