linux-next/include/linux/mmdebug.h
Masahiro Yamada dbefa1f31a Rename .data.once to .data..once to fix resetting WARN*_ONCE
Commit b1fca27d38 ("kernel debug: support resetting WARN*_ONCE")
added support for clearing the state of once warnings. However,
it is not functional when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION or
CONFIG_LTO_CLANG is enabled, because .data.once matches the
.data.[0-9a-zA-Z_]* pattern in the DATA_MAIN macro.

Commit cb87481ee8 ("kbuild: linker script do not match C names unless
LD_DEAD_CODE_DATA_ELIMINATION is configured") was introduced to suppress
the issue for the default CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=n case,
providing a minimal fix for stable backporting. We were aware this did
not address the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. The
plan was to apply correct fixes and then revert cb87481ee8. [1]

Seven years have passed since then, yet the #ifdef workaround remains in
place. Meanwhile, commit b1fca27d38 introduced the .data.once section,
and commit dc5723b02e ("kbuild: add support for Clang LTO") extended
the #ifdef.

Using a ".." separator in the section name fixes the issue for
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION and CONFIG_LTO_CLANG.

[1]: https://lore.kernel.org/linux-kbuild/CAK7LNASck6BfdLnESxXUeECYL26yUDm0cwRZuM4gmaWUkxjL5g@mail.gmail.com/

Fixes: b1fca27d38 ("kernel debug: support resetting WARN*_ONCE")
Fixes: dc5723b02e ("kbuild: add support for Clang LTO")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-11-27 09:38:27 +09:00

130 lines
3.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_MM_DEBUG_H
#define LINUX_MM_DEBUG_H 1
#include <linux/bug.h>
#include <linux/stringify.h>
struct page;
struct vm_area_struct;
struct mm_struct;
struct vma_iterator;
void dump_page(const struct page *page, const char *reason);
void dump_vma(const struct vm_area_struct *vma);
void dump_mm(const struct mm_struct *mm);
void vma_iter_dump_tree(const struct vma_iterator *vmi);
#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
#define VM_BUG_ON_PAGE(cond, page) \
do { \
if (unlikely(cond)) { \
dump_page(page, "VM_BUG_ON_PAGE(" __stringify(cond)")");\
BUG(); \
} \
} while (0)
#define VM_BUG_ON_FOLIO(cond, folio) \
do { \
if (unlikely(cond)) { \
dump_page(&folio->page, "VM_BUG_ON_FOLIO(" __stringify(cond)")");\
BUG(); \
} \
} while (0)
#define VM_BUG_ON_VMA(cond, vma) \
do { \
if (unlikely(cond)) { \
dump_vma(vma); \
BUG(); \
} \
} while (0)
#define VM_BUG_ON_MM(cond, mm) \
do { \
if (unlikely(cond)) { \
dump_mm(mm); \
BUG(); \
} \
} while (0)
#define VM_WARN_ON_ONCE_PAGE(cond, page) ({ \
static bool __section(".data..once") __warned; \
int __ret_warn_once = !!(cond); \
\
if (unlikely(__ret_warn_once && !__warned)) { \
dump_page(page, "VM_WARN_ON_ONCE_PAGE(" __stringify(cond)")");\
__warned = true; \
WARN_ON(1); \
} \
unlikely(__ret_warn_once); \
})
#define VM_WARN_ON_FOLIO(cond, folio) ({ \
int __ret_warn = !!(cond); \
\
if (unlikely(__ret_warn)) { \
dump_page(&folio->page, "VM_WARN_ON_FOLIO(" __stringify(cond)")");\
WARN_ON(1); \
} \
unlikely(__ret_warn); \
})
#define VM_WARN_ON_ONCE_FOLIO(cond, folio) ({ \
static bool __section(".data..once") __warned; \
int __ret_warn_once = !!(cond); \
\
if (unlikely(__ret_warn_once && !__warned)) { \
dump_page(&folio->page, "VM_WARN_ON_ONCE_FOLIO(" __stringify(cond)")");\
__warned = true; \
WARN_ON(1); \
} \
unlikely(__ret_warn_once); \
})
#define VM_WARN_ON_ONCE_MM(cond, mm) ({ \
static bool __section(".data..once") __warned; \
int __ret_warn_once = !!(cond); \
\
if (unlikely(__ret_warn_once && !__warned)) { \
dump_mm(mm); \
__warned = true; \
WARN_ON(1); \
} \
unlikely(__ret_warn_once); \
})
#define VM_WARN_ON(cond) (void)WARN_ON(cond)
#define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
#define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
#define VM_WARN(cond, format...) (void)WARN(cond, format)
#else
#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
#define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
#define VM_BUG_ON_FOLIO(cond, folio) VM_BUG_ON(cond)
#define VM_BUG_ON_VMA(cond, vma) VM_BUG_ON(cond)
#define VM_BUG_ON_MM(cond, mm) VM_BUG_ON(cond)
#define VM_WARN_ON(cond) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ON_ONCE_PAGE(cond, page) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ON_FOLIO(cond, folio) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ON_ONCE_FOLIO(cond, folio) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ON_ONCE_MM(cond, mm) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN(cond, format...) BUILD_BUG_ON_INVALID(cond)
#endif
#ifdef CONFIG_DEBUG_VM_IRQSOFF
#define VM_WARN_ON_IRQS_ENABLED() WARN_ON_ONCE(!irqs_disabled())
#else
#define VM_WARN_ON_IRQS_ENABLED() do { } while (0)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL
#define VIRTUAL_BUG_ON(cond) BUG_ON(cond)
#else
#define VIRTUAL_BUG_ON(cond) do { } while (0)
#endif
#ifdef CONFIG_DEBUG_VM_PGFLAGS
#define VM_BUG_ON_PGFLAGS(cond, page) VM_BUG_ON_PAGE(cond, page)
#else
#define VM_BUG_ON_PGFLAGS(cond, page) BUILD_BUG_ON_INVALID(cond)
#endif
#endif