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f627b51aaa
In order to support Clang's stack depth tracking (for Linux's kstack_erase
feature), the coverage sanitizer needed to be disabled for __init (and
__head) section code. Doing this universally (i.e. for GCC too) created
a number of unexpected problems, ranging from changes to inlining logic
to failures to DCE code on earlier GCC versions.
Since this change is only needed for Clang, specialize it so that GCC
doesn't see the change as it isn't needed there (the GCC implementation
of kstack_erase uses a GCC plugin that removes stack depth tracking
instrumentation from __init sections during a late pass in the IR).
Successfully build and boot tested with GCC 12 and Clang 22.
Fixes: 381a38ea53 ("init.h: Disable sanitizer coverage for __init and __head")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202507270258.neWuiXLd-lkp@intel.com/
Reported-by: syzbot+5245cb609175fb6e8122@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6888d004.a00a0220.26d0e1.0004.GAE@google.com/
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20250729234055.it.233-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
26 lines
1,022 B
C
26 lines
1,022 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_INIT_H
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#define _ASM_X86_INIT_H
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#if defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 170000
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#define __head __section(".head.text") __no_sanitize_undefined __no_stack_protector
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#else
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#define __head __section(".head.text") __no_sanitize_undefined __no_kstack_erase
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#endif
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struct x86_mapping_info {
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void *(*alloc_pgt_page)(void *); /* allocate buf for page table */
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void (*free_pgt_page)(void *, void *); /* free buf for page table */
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void *context; /* context for alloc_pgt_page */
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unsigned long page_flag; /* page flag for PMD or PUD entry */
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unsigned long offset; /* ident mapping offset */
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bool direct_gbpages; /* PUD level 1GB page support */
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unsigned long kernpg_flag; /* kernel pagetable flag override */
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};
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int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
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unsigned long pstart, unsigned long pend);
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void kernel_ident_mapping_free(struct x86_mapping_info *info, pgd_t *pgd);
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#endif /* _ASM_X86_INIT_H */
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