[PATCH] x86_64: Add compat_printk and sysctl to turn off compat layer warnings
Sometimes e.g. with crashme the compat layer warnings can be noisy.
Add a way to turn them off by gating all output through compat_printk
that checks a global sysctl. The default is not changed.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/ia32/sys_ia32.c b/arch/x86_64/ia32/sys_ia32.c
index f182b20..ee30557 100644
--- a/arch/x86_64/ia32/sys_ia32.c
+++ b/arch/x86_64/ia32/sys_ia32.c
@@ -514,7 +514,7 @@
static char lastcomm[sizeof(me->comm)];
if (strncmp(lastcomm, me->comm, sizeof(lastcomm))) {
- printk(KERN_INFO "IA32 syscall %d from %s not implemented\n",
+ compat_printk(KERN_INFO "IA32 syscall %d from %s not implemented\n",
call, me->comm);
strncpy(lastcomm, me->comm, sizeof(lastcomm));
}
@@ -916,7 +916,7 @@
struct task_struct *me = current;
static char lastcomm[sizeof(me->comm)];
if (strncmp(lastcomm, me->comm, sizeof(lastcomm))) {
- printk(KERN_INFO "%s: vm86 mode not supported on 64 bit kernel\n",
+ compat_printk(KERN_INFO "%s: vm86 mode not supported on 64 bit kernel\n",
me->comm);
strncpy(lastcomm, me->comm, sizeof(lastcomm));
}
diff --git a/fs/compat.c b/fs/compat.c
index 7e7e5bc..e31e9cf 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -55,6 +55,20 @@
extern void sigset_from_compat(sigset_t *set, compat_sigset_t *compat);
+int compat_log = 1;
+
+int compat_printk(const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+ if (!compat_log)
+ return 0;
+ va_start(ap, fmt);
+ ret = vprintk(fmt, ap);
+ va_end(ap);
+ return ret;
+}
+
/*
* Not all architectures have sys_utime, so implement this in terms
* of sys_utimes.
@@ -359,7 +373,7 @@
sprintf(buf,"'%c'", (cmd>>24) & 0x3f);
if (!isprint(buf[1]))
sprintf(buf, "%02x", buf[1]);
- printk("ioctl32(%s:%d): Unknown cmd fd(%d) "
+ compat_printk("ioctl32(%s:%d): Unknown cmd fd(%d) "
"cmd(%08x){%s} arg(%08x) on %s\n",
current->comm, current->pid,
(int)fd, (unsigned int)cmd, buf,
diff --git a/include/linux/compat.h b/include/linux/compat.h
index dda1697..9760753 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -226,5 +226,7 @@
asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
+extern int compat_printk(const char *fmt, ...);
+
#endif /* CONFIG_COMPAT */
#endif /* _LINUX_COMPAT_H */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 6a60770..349ef90 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -148,9 +148,11 @@
KERN_SPIN_RETRY=70, /* int: number of spinlock retries */
KERN_ACPI_VIDEO_FLAGS=71, /* int: flags for setting up video after ACPI sleep */
KERN_IA64_UNALIGNED=72, /* int: ia64 unaligned userland trap enable */
+ KERN_COMPAT_LOG=73, /* int: print compat layer messages */
};
+
/* CTL_VM names: */
enum
{
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 2c0e658..f1a4eb1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -73,6 +73,7 @@
extern int pid_max_min, pid_max_max;
extern int sysctl_drop_caches;
extern int percpu_pagelist_fraction;
+extern int compat_log;
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
int unknown_nmi_panic;
@@ -677,6 +678,16 @@
.proc_handler = &proc_dointvec,
},
#endif
+#ifdef CONFIG_COMPAT
+ {
+ .ctl_name = KERN_COMPAT_LOG,
+ .procname = "compat-log",
+ .data = &compat_log,
+ .maxlen = sizeof (int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+#endif
{ .ctl_name = 0 }
};