[IA64] sysctl option to silence unaligned trap warnings

Allow sysadmin to disable all warnings about userland apps making unaligned accesses by using: # echo 1 > /proc/sys/kernel/ignore-unaligned-usertrap Rather than having to use prctl on a process by process basis. Default behaivour leaves the warnings enabled.

Jes Sorensen committed 20 years ago

Commit d2b176e1 parent c8c16353 files · +43 −3Browse files

Unified · Split

3 files

arch/ia64/kernel/unaligned.c +28 −3
include/linux/sysctl.h +1 −0
kernel/sysctl.c +14 −0

arch/ia64/kernel/unaligned.c+28−3

@@ -52,6 +52,15 @@ dump (const char str, void vp, size_t len) · 51 unmodified lines
52	#define IA64_FIRST_ROTATING_FR 32	52	#define IA64_FIRST_ROTATING_FR 32
53	#define SIGN_EXT9 0xffffffffffffff00ul	53	#define SIGN_EXT9 0xffffffffffffff00ul
54		54
		55	/*
		56	* sysctl settable hook which tells the kernel whether to honor the
		57	* IA64_THREAD_UAC_NOPRINT prctl. Because this is user settable, we want
		58	* to allow the super user to enable/disable this for security reasons
		59	* (i.e. don't allow attacker to fill up logs with unaligned accesses).
		60	*/
		61	int no_unaligned_warning;
		62	static int noprint_warning;
		63
55	/*	64	/*
56	* For M-unit:	65	* For M-unit:
57	*	66	*
@@ -1324,8 +1333,9 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs) · 1266 unmodified lines
1324	if ((current->thread.flags & IA64_THREAD_UAC_SIGBUS) != 0)	1333	if ((current->thread.flags & IA64_THREAD_UAC_SIGBUS) != 0)
1325	goto force_sigbus;	1334	goto force_sigbus;
1326		1335
1327	if (!(current->thread.flags & IA64_THREAD_UAC_NOPRINT)	1336	if (!no_unaligned_warning &&
1328	&& within_logging_rate_limit())	1337	!(current->thread.flags & IA64_THREAD_UAC_NOPRINT) &&
		1338	within_logging_rate_limit())
1329	{	1339	{
1330	char buf[200]; /* comm[] is at most 16 bytes... */	1340	char buf[200]; /* comm[] is at most 16 bytes... */
1331	size_t len;	1341	size_t len;
@@ -1340,7 +1350,22 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs) · 8 unmodified lines
1340	if (user_mode(regs))	1350	if (user_mode(regs))
1341	tty_write_message(current->signal->tty, buf);	1351	tty_write_message(current->signal->tty, buf);
1342	buf[len-1] = '\0'; /* drop '\r' */	1352	buf[len-1] = '\0'; /* drop '\r' */
1343	printk(KERN_WARNING "%s", buf); /* watch for command names containing %s */	1353	/* watch for command names containing %s */
		1354	printk(KERN_WARNING "%s", buf);
		1355	} else {
		1356	if (no_unaligned_warning && !noprint_warning) {
		1357	noprint_warning = 1;
		1358	printk(KERN_WARNING "%s(%d) encountered an "
		1359	"unaligned exception which required\n"
		1360	"kernel assistance, which degrades "
		1361	"the performance of the application.\n"
		1362	"Unaligned exception warnings have "
		1363	"been disabled by the system "
		1364	"administrator\n"
		1365	"echo 0 > /proc/sys/kernel/ignore-"
		1366	"unaligned-usertrap to re-enable\n",
		1367	current->comm, current->pid);
		1368	}
1344	}	1369	}
1345	} else {	1370	} else {
1346	if (within_logging_rate_limit())	1371	if (within_logging_rate_limit())

include/linux/sysctl.h+1−0

@@ -147,6 +147,7 @@ enum · 146 unmodified lines
147	KERN_SETUID_DUMPABLE=69, /* int: behaviour of dumps for setuid core */	147	KERN_SETUID_DUMPABLE=69, /* int: behaviour of dumps for setuid core */
148	KERN_SPIN_RETRY=70, /* int: number of spinlock retries */	148	KERN_SPIN_RETRY=70, /* int: number of spinlock retries */
149	KERN_ACPI_VIDEO_FLAGS=71, /* int: flags for setting up video after ACPI sleep */	149	KERN_ACPI_VIDEO_FLAGS=71, /* int: flags for setting up video after ACPI sleep */
		150	KERN_IA64_UNALIGNED=72, /* int: ia64 unaligned userland trap enable */
150	};	151	};
151		152
152		153

kernel/sysctl.c+14−0

@@ -124,6 +124,10 @@ extern int sysctl_hz_timer; · 123 unmodified lines
124	extern int acct_parm[];	124	extern int acct_parm[];
125	#endif	125	#endif
126		126
		127	#ifdef CONFIG_IA64
		128	extern int no_unaligned_warning;
		129	#endif
		130
127	static int parse_table(int __user , int, void __user , size_t __user , void __user , size_t,	131	static int parse_table(int __user , int, void __user , size_t __user , void __user , size_t,
128	ctl_table , void *);	132	ctl_table , void *);
129	static int proc_doutsstring(ctl_table table, int write, struct file filp,	133	static int proc_doutsstring(ctl_table table, int write, struct file filp,
@@ -665,6 +669,16 @@ static ctl_table kern_table[] = { · 535 unmodified lines
665	.mode = 0644,	669	.mode = 0644,
666	.proc_handler = &proc_dointvec,	670	.proc_handler = &proc_dointvec,
667	},	671	},
		672	#endif
		673	#ifdef CONFIG_IA64
		674	{
		675	.ctl_name = KERN_IA64_UNALIGNED,
		676	.procname = "ignore-unaligned-usertrap",
		677	.data = &no_unaligned_warning,
		678	.maxlen = sizeof (int),
		679	.mode = 0644,
		680	.proc_handler = &proc_dointvec,
		681	},
668	#endif	682	#endif
669	{ .ctl_name = 0 }	683	{ .ctl_name = 0 }
670	};	684	};