Re: [PATCH v2] arch, mm: promote DEBUG_WX to CHECK_WX

From: Anshuman Khandual

Date: Wed Sep 30 2026 - 23:17:48 EST

On Wed, Sep 30, 2026 at 11:51:07AM +0200, Mike Rapoport wrote:
> Hi Anshuman,
>
> On Mon, Sep 28, 2026 at 11:24:40AM +0530, Anshuman Khandual wrote:
> > On Sat, Sep 26, 2026 at 12:29:29PM +0300, Mike Rapoport (Microsoft) wrote:
> > > Verification that the kernel does not have writable + executable
> > > mappings is about detecting security risks rather than a pure debug
> > > feature.
> > >
> > > Major distribution configurations enable it in their kernels as well as
> > > defconfigs of most architectures that have ARCH_HAS_DEBUG_WX.
> > >
> > > Rename relevant generic configuration options to use CHECK_WX and move
> > > their definitions from mm/Kconfig.debug to mm/Kconfig.
> > >
> > > Rename *debug_checkwx() funcitons and macros to *pgtable_checkwx().
> >
> > A small nit - pgtable_ckeck_wx() might be better and also consistent with
> > renamed config CHECK_WX ?
>
> Yeah, we could, but I wouldn't want to send v3 just for this.

Fair enough - no problem.

>
> > > For arm that does not widely enable it, only rename its variants of the
> > > config options.
> > >
> > > Enabling CHECK_WX adds a few kilobytes to the kernel binary and while
> > > the added size can be slightly reduced with churny updates of
> > > architecture implementations of ptdump, the core functionality takes
> > > most of the added size. It cannot be moved to .init.text because the
> > > verification has to happen after init sections are freed.
> > >
> > > With this, make generic CHECK_WX default to STRICT_KERNEL_RWX while
> > > still leaving users targeting small kernels the possibility to opt-out.
> >
> > Although the commit message clearly spells out "promote" DEBUG_WX but still
> > wondering would it be better to split this change into two patches instead.
> >
> > - Rename DEBUG_WX as CHECK_WX including all depenencies and helpers
> > - Change CHECK_WX behaviour like defaulting with STRICT_KERNEL_RWX which
> > was not the case earlier
>
> I think a single patch is better to keep it all together. The point here is to
> actually enable the check by default, and the renaming is kinda a side
> effect.

Alright - probably better to keep these changes together in a single commit.

>
> > >
> > > Suggested-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> > > ---
> > > Changes in v2:
> > > - add rename of *debug_checkwx() to *pgtable_checkwx()
> > > - Link to v1: https://patch.msgid.link/20260925-direct-map-verify-wx-v1-1-7fd2f7d6d23b@xxxxxxxxxx
> > > ---
> > > arch/arm/Kconfig.debug | 2 +-
> > > arch/arm/configs/aspeed_g4_defconfig | 2 +-
> > > arch/arm/configs/aspeed_g5_defconfig | 2 +-
> > > arch/arm/configs/shmobile_defconfig | 2 +-
> > > arch/arm/include/asm/ptdump.h | 6 +++---
> > > arch/arm/mm/init.c | 2 +-
> > > arch/arm64/Kconfig | 2 +-
> > > arch/powerpc/Kconfig | 2 +-
> > > arch/powerpc/configs/ppc64_defconfig | 2 +-
> > > arch/powerpc/mm/ptdump/ptdump.c | 2 +-
> > > arch/riscv/Kconfig | 2 +-
> > > arch/s390/Kconfig | 2 +-
> > > arch/s390/configs/debug_defconfig | 2 +-
> > > arch/s390/configs/defconfig | 2 +-
> > > arch/s390/mm/dump_pagetables.c | 2 +-
> > > arch/x86/Kconfig | 2 +-
> > > arch/x86/configs/x86_64_defconfig | 2 +-
> > > arch/x86/include/asm/pgtable.h | 6 +++---
> > > arch/x86/mm/pti.c | 2 +-
> > > include/linux/ptdump.h | 4 ++--
> > > init/main.c | 2 +-
> > > kernel/configs/debug.config | 2 +-
> > > mm/Kconfig | 41 ++++++++++++++++++++++++++++++++++++
> > > mm/Kconfig.debug | 39 ----------------------------------
> > > 24 files changed, 68 insertions(+), 66 deletions(-)
> > >
> > > diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
> > > index 366f162e147d..abcf14f10276 100644
> > > --- a/arch/arm/Kconfig.debug
> > > +++ b/arch/arm/Kconfig.debug
> > > @@ -17,7 +17,7 @@ config ARM_PTDUMP_DEBUGFS
> > > kernel.
> > > If in doubt, say "N"
> > >
> > > -config ARM_DEBUG_WX
> > > +config ARM_CHECK_WX
> > > bool "Warn on W+X mappings at boot"
> > > depends on MMU
> > > select ARM_PTDUMP_CORE
> > > diff --git a/arch/arm/configs/aspeed_g4_defconfig b/arch/arm/configs/aspeed_g4_defconfig
> > > index f86dd4ce7d0d..2c9d5a644ae9 100644
> > > --- a/arch/arm/configs/aspeed_g4_defconfig
> > > +++ b/arch/arm/configs/aspeed_g4_defconfig
> > > @@ -249,7 +249,7 @@ CONFIG_DEBUG_INFO_REDUCED=y
> > > CONFIG_GDB_SCRIPTS=y
> > > CONFIG_STRIP_ASM_SYMS=y
> > > CONFIG_DEBUG_FS=y
> > > -CONFIG_ARM_DEBUG_WX=y
> > > +CONFIG_ARM_CHECK_WX=y
> > > CONFIG_SCHED_STACK_END_CHECK=y
> > > CONFIG_PANIC_ON_OOPS=y
> > > CONFIG_PANIC_TIMEOUT=-1
> > > diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
> > > index 45b937419dbd..1327a09e163a 100644
> > > --- a/arch/arm/configs/aspeed_g5_defconfig
> > > +++ b/arch/arm/configs/aspeed_g5_defconfig
> > > @@ -300,7 +300,7 @@ CONFIG_DEBUG_INFO_REDUCED=y
> > > CONFIG_GDB_SCRIPTS=y
> > > CONFIG_STRIP_ASM_SYMS=y
> > > CONFIG_DEBUG_FS=y
> > > -CONFIG_ARM_DEBUG_WX=y
> > > +CONFIG_ARM_CHECK_WX=y
> > > CONFIG_SCHED_STACK_END_CHECK=y
> > > CONFIG_PANIC_ON_OOPS=y
> > > CONFIG_PANIC_TIMEOUT=-1
> > > diff --git a/arch/arm/configs/shmobile_defconfig b/arch/arm/configs/shmobile_defconfig
> > > index 6f9696e9fe17..cc22e22b989e 100644
> > > --- a/arch/arm/configs/shmobile_defconfig
> > > +++ b/arch/arm/configs/shmobile_defconfig
> > > @@ -225,4 +225,4 @@ CONFIG_CMA_SIZE_MBYTES=64
> > > CONFIG_PRINTK_TIME=y
> > > CONFIG_DEBUG_KERNEL=y
> > > CONFIG_DEBUG_FS=y
> > > -CONFIG_ARM_DEBUG_WX=y
> > > +CONFIG_ARM_CHECK_WX=y
> > > diff --git a/arch/arm/include/asm/ptdump.h b/arch/arm/include/asm/ptdump.h
> > > index 46a4575146ee..3c5245220ecf 100644
> > > --- a/arch/arm/include/asm/ptdump.h
> > > +++ b/arch/arm/include/asm/ptdump.h
> > > @@ -32,10 +32,10 @@ void ptdump_check_wx(void);
> > >
> > > #endif /* CONFIG_ARM_PTDUMP_CORE */
> > >
> > > -#ifdef CONFIG_ARM_DEBUG_WX
> > > -#define arm_debug_checkwx() ptdump_check_wx()
> > > +#ifdef CONFIG_ARM_CHECK_WX
> > > +#define arm_pgtable_checkwx() ptdump_check_wx()
> > > #else
> > > -#define arm_debug_checkwx() do { } while (0)
> > > +#define arm_pgtable_checkwx() do { } while (0)
> > > #endif
> > >
> > > #endif /* __ASM_PTDUMP_H */
> > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> > > index 0cc1bf04686d..c515faf22eeb 100644
> > > --- a/arch/arm/mm/init.c
> > > +++ b/arch/arm/mm/init.c
> > > @@ -403,7 +403,7 @@ static int __mark_rodata_ro(void *unused)
> > > void mark_rodata_ro(void)
> > > {
> > > stop_machine(__mark_rodata_ro, NULL, NULL);
> > > - arm_debug_checkwx();
> > > + arm_pgtable_checkwx();
> > > }
> > >
> > > #else
> > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > > index b5a51b0ef944..7e120fb21c58 100644
> > > --- a/arch/arm64/Kconfig
> > > +++ b/arch/arm64/Kconfig
> > > @@ -11,7 +11,7 @@ config ARM64
> > > select ACPI_MCFG if (ACPI && PCI)
> > > select ACPI_SPCR_TABLE if ACPI
> > > select ACPI_PPTT if ACPI
> > > - select ARCH_HAS_DEBUG_WX
> > > + select ARCH_HAS_CHECK_WX
> > > select ARCH_BINFMT_ELF_EXTRA_PHDRS
> > > select ARCH_BINFMT_ELF_STATE
> > > select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
> > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > > index 2580e27e4328..7c1fe5b4cd41 100644
> > > --- a/arch/powerpc/Kconfig
> > > +++ b/arch/powerpc/Kconfig
> > > @@ -130,7 +130,7 @@ config PPC
> > > select ARCH_HAS_CURRENT_STACK_POINTER
> > > select ARCH_HAS_DEBUG_VIRTUAL
> > > select ARCH_HAS_DEBUG_VM_PGTABLE
> > > - select ARCH_HAS_DEBUG_WX if STRICT_KERNEL_RWX
> > > + select ARCH_HAS_CHECK_WX if STRICT_KERNEL_RWX
> > > select ARCH_HAS_DEVMEM_IS_ALLOWED
> > > select ARCH_HAS_DMA_MAP_DIRECT if PPC_PSERIES
> > > select ARCH_HAS_DMA_OPS if PPC64
> > > diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
> > > index 1eb8e3457e8b..5c33f0bba0e3 100644
> > > --- a/arch/powerpc/configs/ppc64_defconfig
> > > +++ b/arch/powerpc/configs/ppc64_defconfig
> > > @@ -393,7 +393,7 @@ CONFIG_MAGIC_SYSRQ=y
> > > CONFIG_PAGE_OWNER=y
> > > CONFIG_PAGE_POISONING=y
> > > CONFIG_DEBUG_RODATA_TEST=y
> > > -CONFIG_DEBUG_WX=y
> > > +CONFIG_CHECK_WX=y
> > > CONFIG_DEBUG_STACK_USAGE=y
> > > CONFIG_DEBUG_VM=y
> > > # CONFIG_DEBUG_VM_PGTABLE is not set
> > > diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
> > > index 0d499aebee72..3451351b756b 100644
> > > --- a/arch/powerpc/mm/ptdump/ptdump.c
> > > +++ b/arch/powerpc/mm/ptdump/ptdump.c
> > > @@ -191,7 +191,7 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr)
> > > if (!pte_write(pte) || !pte_exec(pte))
> > > return;
> > >
> > > - WARN_ONCE(IS_ENABLED(CONFIG_DEBUG_WX),
> > > + WARN_ONCE(IS_ENABLED(CONFIG_CHECK_WX),
> > > "powerpc/mm: Found insecure W+X mapping at address %p/%pS\n",
> > > (void *)st->start_address, (void *)st->start_address);
> > >
> > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > > index d6c2dbf8455c..05e33d4d5efa 100644
> > > --- a/arch/riscv/Kconfig
> > > +++ b/arch/riscv/Kconfig
> > > @@ -29,7 +29,7 @@ config RISCV
> > > select ARCH_HAS_CURRENT_STACK_POINTER
> > > select ARCH_HAS_DEBUG_VIRTUAL if MMU
> > > select ARCH_HAS_DEBUG_VM_PGTABLE
> > > - select ARCH_HAS_DEBUG_WX
> > > + select ARCH_HAS_CHECK_WX
> > > select ARCH_HAS_DELAY_TIMER
> > > select ARCH_HAS_ELF_CORE_EFLAGS if BINFMT_ELF && ELF_CORE
> > > select ARCH_HAS_FAST_MULTIPLIER
> > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> > > index 4b51bc6e8948..11b76f2b0f80 100644
> > > --- a/arch/s390/Kconfig
> > > +++ b/arch/s390/Kconfig
> > > @@ -92,7 +92,7 @@ config S390
> > > select ARCH_HAS_CURRENT_STACK_POINTER
> > > select ARCH_HAS_DEBUG_VIRTUAL
> > > select ARCH_HAS_DEBUG_VM_PGTABLE
> > > - select ARCH_HAS_DEBUG_WX
> > > + select ARCH_HAS_CHECK_WX
> > > select ARCH_HAS_DEVMEM_IS_ALLOWED
> > > select ARCH_HAS_DMA_OPS if PCI
> > > select ARCH_HAS_ELF_RANDOMIZE
> > > diff --git a/arch/s390/configs/debug_defconfig b/arch/s390/configs/debug_defconfig
> > > index 3dae71474333..68d53c0bc8db 100644
> > > --- a/arch/s390/configs/debug_defconfig
> > > +++ b/arch/s390/configs/debug_defconfig
> > > @@ -841,7 +841,7 @@ CONFIG_DEBUG_PAGEALLOC=y
> > > CONFIG_SLUB_DEBUG_ON=y
> > > CONFIG_PAGE_OWNER=y
> > > CONFIG_DEBUG_RODATA_TEST=y
> > > -CONFIG_DEBUG_WX=y
> > > +CONFIG_CHECK_WX=y
> > > CONFIG_PTDUMP_DEBUGFS=y
> > > CONFIG_DEBUG_OBJECTS=y
> > > CONFIG_DEBUG_OBJECTS_SELFTEST=y
> > > diff --git a/arch/s390/configs/defconfig b/arch/s390/configs/defconfig
> > > index 6f5722634b4d..8e5cfc695121 100644
> > > --- a/arch/s390/configs/defconfig
> > > +++ b/arch/s390/configs/defconfig
> > > @@ -820,7 +820,7 @@ CONFIG_DEBUG_INFO_DWARF4=y
> > > CONFIG_GDB_SCRIPTS=y
> > > CONFIG_DEBUG_SECTION_MISMATCH=y
> > > CONFIG_MAGIC_SYSRQ=y
> > > -CONFIG_DEBUG_WX=y
> > > +CONFIG_CHECK_WX=y
> > > CONFIG_PTDUMP_DEBUGFS=y
> > > CONFIG_DEBUG_MEMORY_INIT=y
> > > CONFIG_PANIC_ON_OOPS=y
> > > diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c
> > > index 89badbe72ae7..a23a0bd4d8a8 100644
> > > --- a/arch/s390/mm/dump_pagetables.c
> > > +++ b/arch/s390/mm/dump_pagetables.c
> > > @@ -86,7 +86,7 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr)
> > > */
> > > if (addr == PAGE_SIZE && (nospec_uses_trampoline() || !cpu_has_bear()))
> > > return;
> > > - WARN_ONCE(IS_ENABLED(CONFIG_DEBUG_WX),
> > > + WARN_ONCE(IS_ENABLED(CONFIG_CHECK_WX),
> > > "s390/mm: Found insecure W+X mapping at address %pS\n",
> > > (void *)st->start_address);
> > > st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > > index 15fd9ec5ecac..170cfcb06174 100644
> > > --- a/arch/x86/Kconfig
> > > +++ b/arch/x86/Kconfig
> > > @@ -110,7 +110,7 @@ config X86
> > > select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
> > > select ARCH_HAS_SYSCALL_WRAPPER
> > > select ARCH_HAS_UBSAN
> > > - select ARCH_HAS_DEBUG_WX
> > > + select ARCH_HAS_CHECK_WX
> > > select ARCH_HAS_ZONE_DMA_SET if EXPERT
> > > select ARCH_HAVE_NMI_SAFE_CMPXCHG
> > > select ARCH_HAVE_EXTRA_ELF_NOTES
> > > diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
> > > index 269f7d808be4..e6896aeb77d8 100644
> > > --- a/arch/x86/configs/x86_64_defconfig
> > > +++ b/arch/x86/configs/x86_64_defconfig
> > > @@ -263,7 +263,7 @@ CONFIG_SECURITY_SELINUX_BOOTPARAM=y
> > > CONFIG_PRINTK_TIME=y
> > > CONFIG_DEBUG_KERNEL=y
> > > CONFIG_MAGIC_SYSRQ=y
> > > -CONFIG_DEBUG_WX=y
> > > +CONFIG_CHECK_WX=y
> > > CONFIG_DEBUG_STACK_USAGE=y
> > > CONFIG_SCHEDSTATS=y
> > > CONFIG_BLK_DEV_IO_TRACE=y
> > > diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> > > index d551120a7c88..ef0252a09c28 100644
> > > --- a/arch/x86/include/asm/pgtable.h
> > > +++ b/arch/x86/include/asm/pgtable.h
> > > @@ -41,10 +41,10 @@ void ptdump_walk_user_pgd_level_checkwx(void);
> > > #define pgprot_encrypted(prot) __pgprot(cc_mkenc(pgprot_val(prot)))
> > > #define pgprot_decrypted(prot) __pgprot(cc_mkdec(pgprot_val(prot)))
> > >
> > > -#ifdef CONFIG_DEBUG_WX
> > > -#define debug_checkwx_user() ptdump_walk_user_pgd_level_checkwx()
> > > +#ifdef CONFIG_CHECK_WX
> > > +#define pgtable_checkwx_user() ptdump_walk_user_pgd_level_checkwx()
> > > #else
> > > -#define debug_checkwx_user() do { } while (0)
> > > +#define pgtable_checkwx_user() do { } while (0)
> > > #endif
> > >
> > > extern spinlock_t pgd_lock;
> > > diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
> > > index 598f553cc871..31055ee6f1de 100644
> > > --- a/arch/x86/mm/pti.c
> > > +++ b/arch/x86/mm/pti.c
> > > @@ -688,5 +688,5 @@ void pti_finalize(void)
> > > pti_clone_entry_text(true);
> > > pti_clone_kernel_text();
> > >
> > > - debug_checkwx_user();
> > > + pgtable_checkwx_user();
> > > }
> > > diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h
> > > index 240bd3bff18d..af18d1459b2f 100644
> > > --- a/include/linux/ptdump.h
> > > +++ b/include/linux/ptdump.h
> > > @@ -31,9 +31,9 @@ bool ptdump_walk_pgd_level_core(struct seq_file *m,
> > > void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd);
> > > bool ptdump_check_wx(void);
> > >
> > > -static inline void debug_checkwx(void)
> > > +static inline void pgtable_checkwx(void)
> > > {
> > > - if (IS_ENABLED(CONFIG_DEBUG_WX))
> > > + if (IS_ENABLED(CONFIG_CHECK_WX))
> > > ptdump_check_wx();
> > > }
> > >
> > > diff --git a/init/main.c b/init/main.c
> > > index 31f2bf54976a..a87a3d52f3e2 100644
> > > --- a/init/main.c
> > > +++ b/init/main.c
> > > @@ -1535,7 +1535,7 @@ static void mark_readonly(void)
> > > flush_module_init_free_work();
> > > jump_label_init_ro();
> > > mark_rodata_ro();
> > > - debug_checkwx();
> > > + pgtable_checkwx();
> > > rodata_test();
> > > } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
> > > pr_info("Kernel memory protection disabled.\n");
> > > diff --git a/kernel/configs/debug.config b/kernel/configs/debug.config
> > > index 307c97ac5fa9..ac878669c193 100644
> > > --- a/kernel/configs/debug.config
> > > +++ b/kernel/configs/debug.config
> > > @@ -50,7 +50,7 @@ CONFIG_DEBUG_NET=y
> > > # CONFIG_DEBUG_PAGEALLOC is not set
> > > # CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF is not set
> > > # CONFIG_DEBUG_RODATA_TEST is not set
> > > -# CONFIG_DEBUG_WX is not set
> > > +# CONFIG_CHECK_WX is not set
> > > # CONFIG_KFENCE is not set
> > > # CONFIG_PAGE_POISONING is not set
> > > # CONFIG_SLUB_STATS is not set
> > > diff --git a/mm/Kconfig b/mm/Kconfig
> > > index 604c58199acb..ffbc641cc31f 100644
> > > --- a/mm/Kconfig
> > > +++ b/mm/Kconfig
> > > @@ -1511,6 +1511,47 @@ config LAZY_MMU_MODE_KUNIT_TEST
> > >
> > > If unsure, say N.
> > >
> > > +config ARCH_HAS_CHECK_WX
> > > + bool
> > > +
> > > +config CHECK_WX
> > > + bool "Warn on W+X mappings at boot"
> > > + default STRICT_KERNEL_RWX
> > > + depends on ARCH_HAS_CHECK_WX
> > > + depends on ARCH_HAS_PTDUMP
> > > + depends on MMU
> > > + select PTDUMP
> > > + help
> > > + Generate a warning if any W+X mappings are found at boot.
> > > +
> > > + This is useful for discovering cases where the kernel is leaving W+X
> > > + mappings after applying NX, as such mappings are a security risk.
> > > +
> > > + Look for a message in dmesg output like this:
> > > +
> > > + <arch>/mm: Checked W+X mappings: passed, no W+X pages found.
> > > +
> > > + or like this, if the check failed:
> > > +
> > > + <arch>/mm: Checked W+X mappings: failed, <N> W+X pages found.
> > > +
> > > + Note that even if the check fails, your kernel is possibly
> > > + still fine, as W+X mappings are not a security hole in
> > > + themselves, what they do is that they make the exploitation
> > > + of other unfixed kernel bugs easier.
> > > +
> > > + There is no runtime or memory usage effect of this option
> > > + once the kernel has booted up - it's a one time check.
> > > +
> > > + If in doubt, say "Y".
> > > +
> > > +config ARCH_HAS_PTDUMP
> > > + bool
> > > +
> > > +config PTDUMP
> > > + bool
> > > +
> > > +
> > > source "mm/damon/Kconfig"
> > >
> > > endmenu
> > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
> > > index 15dca19dd07d..75b44e4a6e36 100644
> > > --- a/mm/Kconfig.debug
> > > +++ b/mm/Kconfig.debug
> > > @@ -180,45 +180,6 @@ config DEBUG_RODATA_TEST
> > > help
> > > This option enables a testcase for the setting rodata read-only.
> > >
> > > -config ARCH_HAS_DEBUG_WX
> > > - bool
> > > -
> > > -config DEBUG_WX
> > > - bool "Warn on W+X mappings at boot"
> > > - depends on ARCH_HAS_DEBUG_WX
> > > - depends on ARCH_HAS_PTDUMP
> > > - depends on MMU
> > > - select PTDUMP
> > > - help
> > > - Generate a warning if any W+X mappings are found at boot.
> > > -
> > > - This is useful for discovering cases where the kernel is leaving W+X
> > > - mappings after applying NX, as such mappings are a security risk.
> > > -
> > > - Look for a message in dmesg output like this:
> > > -
> > > - <arch>/mm: Checked W+X mappings: passed, no W+X pages found.
> > > -
> > > - or like this, if the check failed:
> > > -
> > > - <arch>/mm: Checked W+X mappings: failed, <N> W+X pages found.
> > > -
> > > - Note that even if the check fails, your kernel is possibly
> > > - still fine, as W+X mappings are not a security hole in
> > > - themselves, what they do is that they make the exploitation
> > > - of other unfixed kernel bugs easier.
> > > -
> > > - There is no runtime or memory usage effect of this option
> > > - once the kernel has booted up - it's a one time check.
> > > -
> > > - If in doubt, say "Y".
> > > -
> > > -config ARCH_HAS_PTDUMP
> > > - bool
> > > -
> > > -config PTDUMP
> > > - bool
> > > -
> > > config PTDUMP_DEBUGFS
> > > bool "Export kernel pagetable layout to userspace via debugfs"
> > > depends on DEBUG_KERNEL
> > >
> > > ---
> > > base-commit: 93f51579e7df248780214094418f205253383cc5
> > > change-id: 20260925-direct-map-verify-wx-b81bda879781
> > >
> > > --
> > > Sincerely yours,
> > > Mike.
> > >
>
> --
> Sincerely yours,
> Mike.