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| author | Andi Kleen <ak@linux.intel.com> | 2017-11-18 00:27:03 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-18 01:10:00 +0100 |
| commit | b1fca27d384e8418aac84b39f6f5179aecc1b64f (patch) | |
| tree | e08be97de59a1cbb16df46273aadef161358b8ba /include/asm-generic | |
| parent | sh/boot: add static stack-protector to pre-kernel (diff) | |
| download | linux-b1fca27d384e8418aac84b39f6f5179aecc1b64f.tar.xz linux-b1fca27d384e8418aac84b39f6f5179aecc1b64f.zip | |
kernel debug: support resetting WARN*_ONCE
I like _ONCE warnings because it's guaranteed that they don't flood the
log.
During testing I find it useful to reset the state of the once warnings,
so that I can rerun tests and see if they trigger again, or can
guarantee that a test run always hits the same warnings.
This patch adds a debugfs interface to reset all the _ONCE warnings so
that they appear again:
echo 1 > /sys/kernel/debug/clear_warn_once
This is implemented by putting all the warning booleans into a special
section, and clearing it.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20171017221455.6740-1-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/bug.h | 6 | ||||
| -rw-r--r-- | include/asm-generic/sections.h | 1 | ||||
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 3 |
3 files changed, 7 insertions, 3 deletions
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index af2cc94a61bf..7844b0df88cd 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -130,7 +130,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, #ifndef WARN_ON_ONCE #define WARN_ON_ONCE(condition) ({ \ - static bool __section(.data.unlikely) __warned; \ + static bool __section(.data.once) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ @@ -142,7 +142,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, #endif #define WARN_ONCE(condition, format...) ({ \ - static bool __section(.data.unlikely) __warned; \ + static bool __section(.data.once) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ @@ -153,7 +153,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, }) #define WARN_TAINT_ONCE(condition, taint, format...) ({ \ - static bool __section(.data.unlikely) __warned; \ + static bool __section(.data.once) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 6d9576931084..03cc5f9bba71 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -44,6 +44,7 @@ extern char __entry_text_start[], __entry_text_end[]; extern char __start_rodata[], __end_rodata[]; extern char __irqentry_text_start[], __irqentry_text_end[]; extern char __softirqentry_text_start[], __softirqentry_text_end[]; +extern char __start_once[], __end_once[]; /* Start and end of .ctors section - used for constructor calls. */ extern char __ctors_start[], __ctors_end[]; diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index bdcd1caae092..ee8b707d9fa9 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -223,6 +223,9 @@ MEM_KEEP(init.data) \ MEM_KEEP(exit.data) \ *(.data.unlikely) \ + VMLINUX_SYMBOL(__start_once) = .; \ + *(.data.once) \ + VMLINUX_SYMBOL(__end_once) = .; \ STRUCT_ALIGN(); \ *(__tracepoints) \ /* implement dynamic printk debug */ \ |