From 8aeee85a29e27e043db582bf2ae8e5f42767934f Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Fri, 5 Mar 2010 13:42:55 -0800 Subject: panic: fix panic_timeout accuracy when running on a hypervisor I've had some complaints about panic_timeout being wildly innacurate on shared processor PowerPC partitions (a 3 minute panic_timeout taking 30 minutes). The problem is we loop on mdelay(1) and with a 1ms in 10ms hypervisor timeslice each of these will take 10ms (ie 10x) longer. I expect other platforms with shared processor hypervisors will see the same issue. This patch keeps the old behaviour if we have a panic_blink (only keyboard LEDs right now) and does 1 second mdelays if we don't. Signed-off-by: Anton Blanchard Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/panic.c | 46 ++++++++++++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 16 deletions(-) (limited to 'kernel/panic.c') diff --git a/kernel/panic.c b/kernel/panic.c index c787333282b8..13d966b4c14a 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -36,15 +36,36 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list); EXPORT_SYMBOL(panic_notifier_list); -static long no_blink(long time) -{ - return 0; -} - /* Returns how long it waited in ms */ long (*panic_blink)(long time); EXPORT_SYMBOL(panic_blink); +static void panic_blink_one_second(void) +{ + static long i = 0, end; + + if (panic_blink) { + end = i + MSEC_PER_SEC; + + while (i < end) { + i += panic_blink(i); + mdelay(1); + i++; + } + } else { + /* + * When running under a hypervisor a small mdelay may get + * rounded up to the hypervisor timeslice. For example, with + * a 1ms in 10ms hypervisor timeslice we might inflate a + * mdelay(1) loop by 10x. + * + * If we have nothing to blink, spin on 1 second calls to + * mdelay to avoid this. + */ + mdelay(MSEC_PER_SEC); + } +} + /** * panic - halt the system * @fmt: The text string to print @@ -95,9 +116,6 @@ NORET_TYPE void panic(const char * fmt, ...) bust_spinlocks(0); - if (!panic_blink) - panic_blink = no_blink; - if (panic_timeout > 0) { /* * Delay timeout seconds before rebooting the machine. @@ -105,11 +123,9 @@ NORET_TYPE void panic(const char * fmt, ...) */ printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout); - for (i = 0; i < panic_timeout*1000; ) { + for (i = 0; i < panic_timeout; i++) { touch_nmi_watchdog(); - i += panic_blink(i); - mdelay(1); - i++; + panic_blink_one_second(); } /* * This will not be a clean reboot, with everything @@ -135,11 +151,9 @@ NORET_TYPE void panic(const char * fmt, ...) } #endif local_irq_enable(); - for (i = 0; ; ) { + while (1) { touch_softlockup_watchdog(); - i += panic_blink(i); - mdelay(1); - i++; + panic_blink_one_second(); } } -- cgit v1.3-8-gc7d7 From b2be05273a1744d175bf4b67f6665637bb9ac7a8 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Sat, 3 Apr 2010 19:34:56 +0100 Subject: panic: Allow warnings to set different taint flags WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the flag for TAINT_WARN. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint number as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() now implement __WARN_TAINT(taint) instead of __WARN(). Signed-off-by: Ben Hutchings Acked-by: Helge Deller Tested-by: Paul Mundt Signed-off-by: David Woodhouse --- Documentation/oops-tracing.txt | 1 + arch/parisc/include/asm/bug.h | 8 ++++---- arch/powerpc/include/asm/bug.h | 6 +++--- arch/s390/include/asm/bug.h | 8 ++++---- arch/sh/include/asm/bug.h | 4 ++-- include/asm-generic/bug.h | 34 ++++++++++++++++++++++++++++++++-- kernel/panic.c | 24 ++++++++++++++++++++---- lib/bug.c | 2 +- 8 files changed, 67 insertions(+), 20 deletions(-) (limited to 'kernel/panic.c') diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt index c10c022b911c..069fab3ea4d6 100644 --- a/Documentation/oops-tracing.txt +++ b/Documentation/oops-tracing.txt @@ -256,6 +256,7 @@ characters, each representing a particular tainted value. 9: 'A' if the ACPI table has been overridden. 10: 'W' if a warning has previously been issued by the kernel. + (Though some warnings may set more specific taint flags.) 11: 'C' if a staging driver has been loaded. diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h index 75e46c557a16..72cfdb0cfdd1 100644 --- a/arch/parisc/include/asm/bug.h +++ b/arch/parisc/include/asm/bug.h @@ -44,7 +44,7 @@ #endif #ifdef CONFIG_DEBUG_BUGVERBOSE -#define __WARN() \ +#define __WARN_TAINT(taint) \ do { \ asm volatile("\n" \ "1:\t" PARISC_BUG_BREAK_ASM "\n" \ @@ -54,11 +54,11 @@ "\t.org 2b+%c3\n" \ "\t.popsection" \ : : "i" (__FILE__), "i" (__LINE__), \ - "i" (BUGFLAG_WARNING), \ + "i" (BUGFLAG_TAINT(taint)), \ "i" (sizeof(struct bug_entry)) ); \ } while(0) #else -#define __WARN() \ +#define __WARN_TAINT(taint) \ do { \ asm volatile("\n" \ "1:\t" PARISC_BUG_BREAK_ASM "\n" \ @@ -67,7 +67,7 @@ "\t.short %c0\n" \ "\t.org 2b+%c1\n" \ "\t.popsection" \ - : : "i" (BUGFLAG_WARNING), \ + : : "i" (BUGFLAG_TAINT(taint)), \ "i" (sizeof(struct bug_entry)) ); \ } while(0) #endif diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 2c15212e1700..065c590c991d 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -85,12 +85,12 @@ } \ } while (0) -#define __WARN() do { \ +#define __WARN_TAINT(taint) do { \ __asm__ __volatile__( \ "1: twi 31,0,0\n" \ _EMIT_BUG_ENTRY \ : : "i" (__FILE__), "i" (__LINE__), \ - "i" (BUGFLAG_WARNING), \ + "i" (BUGFLAG_TAINT(taint)), \ "i" (sizeof(struct bug_entry))); \ } while (0) @@ -104,7 +104,7 @@ "1: "PPC_TLNEI" %4,0\n" \ _EMIT_BUG_ENTRY \ : : "i" (__FILE__), "i" (__LINE__), \ - "i" (BUGFLAG_WARNING), \ + "i" (BUGFLAG_TAINT(TAINT_WARN)), \ "i" (sizeof(struct bug_entry)), \ "r" (__ret_warn_on)); \ } \ diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h index 9beeb9db9b23..bf90d1fd97a5 100644 --- a/arch/s390/include/asm/bug.h +++ b/arch/s390/include/asm/bug.h @@ -46,18 +46,18 @@ unreachable(); \ } while (0) -#define __WARN() do { \ - __EMIT_BUG(BUGFLAG_WARNING); \ +#define __WARN_TAINT(taint) do { \ + __EMIT_BUG(BUGFLAG_TAINT(taint)); \ } while (0) #define WARN_ON(x) ({ \ int __ret_warn_on = !!(x); \ if (__builtin_constant_p(__ret_warn_on)) { \ if (__ret_warn_on) \ - __EMIT_BUG(BUGFLAG_WARNING); \ + __WARN(); \ } else { \ if (unlikely(__ret_warn_on)) \ - __EMIT_BUG(BUGFLAG_WARNING); \ + __WARN(); \ } \ unlikely(__ret_warn_on); \ }) diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h index d02c01b3e6b9..6323f864d111 100644 --- a/arch/sh/include/asm/bug.h +++ b/arch/sh/include/asm/bug.h @@ -48,7 +48,7 @@ do { \ "i" (sizeof(struct bug_entry))); \ } while (0) -#define __WARN() \ +#define __WARN_TAINT(taint) \ do { \ __asm__ __volatile__ ( \ "1:\t.short %O0\n" \ @@ -57,7 +57,7 @@ do { \ : "n" (TRAPA_BUG_OPCODE), \ "i" (__FILE__), \ "i" (__LINE__), \ - "i" (BUGFLAG_WARNING), \ + "i" (BUGFLAG_TAINT(taint)), \ "i" (sizeof(struct bug_entry))); \ } while (0) diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 18c435d7c082..c2c9ba032d46 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -25,7 +25,10 @@ struct bug_entry { }; #endif /* __ASSEMBLY__ */ -#define BUGFLAG_WARNING (1<<0) +#define BUGFLAG_WARNING (1 << 0) +#define BUGFLAG_TAINT(taint) (BUGFLAG_WARNING | ((taint) << 8)) +#define BUG_GET_TAINT(bug) ((bug)->flags >> 8) + #endif /* CONFIG_GENERIC_BUG */ /* @@ -56,17 +59,25 @@ struct bug_entry { * appear at runtime. Use the versions with printk format strings * to provide better diagnostics. */ -#ifndef __WARN +#ifndef __WARN_TAINT #ifndef __ASSEMBLY__ extern void warn_slowpath_fmt(const char *file, const int line, const char *fmt, ...) __attribute__((format(printf, 3, 4))); +extern void warn_slowpath_fmt_taint(const char *file, const int line, + unsigned taint, const char *fmt, ...) + __attribute__((format(printf, 4, 5))); extern void warn_slowpath_null(const char *file, const int line); #define WANT_WARN_ON_SLOWPATH #endif #define __WARN() warn_slowpath_null(__FILE__, __LINE__) #define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg) +#define __WARN_printf_taint(taint, arg...) \ + warn_slowpath_fmt_taint(__FILE__, __LINE__, taint, arg) #else +#define __WARN() __WARN_TAINT(TAINT_WARN) #define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0) +#define __WARN_printf_taint(taint, arg...) \ + do { printk(arg); __WARN_TAINT(taint); } while (0) #endif #ifndef WARN_ON @@ -87,6 +98,13 @@ extern void warn_slowpath_null(const char *file, const int line); }) #endif +#define WARN_TAINT(condition, taint, format...) ({ \ + int __ret_warn_on = !!(condition); \ + if (unlikely(__ret_warn_on)) \ + __WARN_printf_taint(taint, format); \ + unlikely(__ret_warn_on); \ +}) + #else /* !CONFIG_BUG */ #ifndef HAVE_ARCH_BUG #define BUG() do {} while(0) @@ -110,6 +128,8 @@ extern void warn_slowpath_null(const char *file, const int line); }) #endif +#define WARN_TAINT(condition, taint, format...) WARN_ON(condition) + #endif #define WARN_ON_ONCE(condition) ({ \ @@ -132,6 +152,16 @@ extern void warn_slowpath_null(const char *file, const int line); unlikely(__ret_warn_once); \ }) +#define WARN_TAINT_ONCE(condition, taint, format...) ({ \ + static bool __warned; \ + int __ret_warn_once = !!(condition); \ + \ + if (unlikely(__ret_warn_once)) \ + if (WARN_TAINT(!__warned, taint, format)) \ + __warned = true; \ + unlikely(__ret_warn_once); \ +}) + #define WARN_ON_RATELIMIT(condition, state) \ WARN_ON((condition) && __ratelimit(state)) diff --git a/kernel/panic.c b/kernel/panic.c index 13d966b4c14a..8b821bce66e6 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -365,7 +365,8 @@ struct slowpath_args { va_list args; }; -static void warn_slowpath_common(const char *file, int line, void *caller, struct slowpath_args *args) +static void warn_slowpath_common(const char *file, int line, void *caller, + unsigned taint, struct slowpath_args *args) { const char *board; @@ -381,7 +382,7 @@ static void warn_slowpath_common(const char *file, int line, void *caller, struc print_modules(); dump_stack(); print_oops_end_marker(); - add_taint(TAINT_WARN); + add_taint(taint); } void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) @@ -390,14 +391,29 @@ void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) args.fmt = fmt; va_start(args.args, fmt); - warn_slowpath_common(file, line, __builtin_return_address(0), &args); + warn_slowpath_common(file, line, __builtin_return_address(0), + TAINT_WARN, &args); va_end(args.args); } EXPORT_SYMBOL(warn_slowpath_fmt); +void warn_slowpath_fmt_taint(const char *file, int line, + unsigned taint, const char *fmt, ...) +{ + struct slowpath_args args; + + args.fmt = fmt; + va_start(args.args, fmt); + warn_slowpath_common(file, line, __builtin_return_address(0), + taint, &args); + va_end(args.args); +} +EXPORT_SYMBOL(warn_slowpath_fmt_taint); + void warn_slowpath_null(const char *file, int line) { - warn_slowpath_common(file, line, __builtin_return_address(0), NULL); + warn_slowpath_common(file, line, __builtin_return_address(0), + TAINT_WARN, NULL); } EXPORT_SYMBOL(warn_slowpath_null); #endif diff --git a/lib/bug.c b/lib/bug.c index 300e41afbf97..f13daf435211 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -165,7 +165,7 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) (void *)bugaddr); show_regs(regs); - add_taint(TAINT_WARN); + add_taint(BUG_GET_TAINT(bug)); return BUG_TRAP_TYPE_WARN; } -- cgit v1.3-8-gc7d7 From 92946bc72f2e74c3281b7fc12be9704d455fb3ed Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Sat, 3 Apr 2010 19:36:42 +0100 Subject: panic: Add taint flag TAINT_FIRMWARE_WORKAROUND ('I') This taint flag will initially be used when warning about invalid ACPI DMAR tables. Signed-off-by: Ben Hutchings Signed-off-by: David Woodhouse --- Documentation/oops-tracing.txt | 3 +++ include/linux/kernel.h | 1 + kernel/panic.c | 2 ++ 3 files changed, 6 insertions(+) (limited to 'kernel/panic.c') diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt index 069fab3ea4d6..6fe9001b9263 100644 --- a/Documentation/oops-tracing.txt +++ b/Documentation/oops-tracing.txt @@ -260,6 +260,9 @@ characters, each representing a particular tainted value. 11: 'C' if a staging driver has been loaded. + 12: 'I' if the kernel is working around a severe bug in the platform + firmware (BIOS or similar). + The primary reason for the 'Tainted: ' string is to tell kernel debuggers if this is a clean kernel or if anything unusual has occurred. Tainting is permanent: even if an offending module is diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 7f0707463360..7f2f7b34dd08 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -344,6 +344,7 @@ extern enum system_states { #define TAINT_OVERRIDDEN_ACPI_TABLE 8 #define TAINT_WARN 9 #define TAINT_CRAP 10 +#define TAINT_FIRMWARE_WORKAROUND 11 extern void dump_stack(void) __cold; diff --git a/kernel/panic.c b/kernel/panic.c index 8b821bce66e6..dbe13dbb057a 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -178,6 +178,7 @@ static const struct tnt tnts[] = { { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, { TAINT_WARN, 'W', ' ' }, { TAINT_CRAP, 'C', ' ' }, + { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' }, }; /** @@ -194,6 +195,7 @@ static const struct tnt tnts[] = { * 'A' - ACPI table overridden. * 'W' - Taint on warning. * 'C' - modules from drivers/staging are loaded. + * 'I' - Working around severe firmware bug. * * The string is overwritten by the next call to print_tainted(). */ -- cgit v1.3-8-gc7d7 From 5b530fc18324602e1ecb70cd280c2194b2656a5e Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Wed, 26 May 2010 14:44:24 -0700 Subject: panic: call console_verbose() in panic Most distros turn the console verbosity down and that means a backtrace after a panic never makes it to the console. I assume we haven't seen this because a panic is often preceeded by an oops which will have called console_verbose. There are however a lot of places we call panic directly, and they are broken. Use console_verbose like we do in the oops path to ensure a directly called panic will print a backtrace. Signed-off-by: Anton Blanchard Acked-by: Greg Kroah-Hartman Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/panic.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/panic.c') diff --git a/kernel/panic.c b/kernel/panic.c index dbe13dbb057a..3b16cd93fa7d 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -87,6 +87,7 @@ NORET_TYPE void panic(const char * fmt, ...) */ preempt_disable(); + console_verbose(); bust_spinlocks(1); va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); -- cgit v1.3-8-gc7d7