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Subject[PATCH 2/6] trace syscalls: Convert redundant syscall_nr checks into WARN_ON
Date
From: Ian Munsie <imunsie@au1.ibm.com>

With the ftrace events now checking if the syscall_nr is valid upon
initialisation it should no longer be possible to register or unregister
a syscall event without a valid syscall_nr since they should not be
created. This adds a WARN_ON_ONCE in the register and unregister
functions to locate potential regressions in the future.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
---
kernel/trace/trace_syscalls.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index a66bc13..1a6e8dd 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -358,7 +358,7 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
int num;

num = ((struct syscall_metadata *)call->data)->syscall_nr;
- if (num < 0 || num >= NR_syscalls)
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
if (!sys_refcount_enter)
@@ -376,7 +376,7 @@ void unreg_event_syscall_enter(struct ftrace_event_call *call)
int num;

num = ((struct syscall_metadata *)call->data)->syscall_nr;
- if (num < 0 || num >= NR_syscalls)
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return;
mutex_lock(&syscall_trace_lock);
sys_refcount_enter--;
@@ -392,7 +392,7 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
int num;

num = ((struct syscall_metadata *)call->data)->syscall_nr;
- if (num < 0 || num >= NR_syscalls)
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
if (!sys_refcount_exit)
@@ -410,7 +410,7 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call)
int num;

num = ((struct syscall_metadata *)call->data)->syscall_nr;
- if (num < 0 || num >= NR_syscalls)
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return;
mutex_lock(&syscall_trace_lock);
sys_refcount_exit--;
--
1.7.2.3


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