Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'x86_urgent_for_v5.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
"A single fix for early boot crashes of kernels built with gcc10 and
stack protector enabled"
* tag 'x86_urgent_for_v5.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Fix early boot crash on gcc-10, third try
+23
-1
+6
-1
arch/x86/include/asm/stackprotector.h
+6
-1
arch/x86/include/asm/stackprotector.h
···
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/*
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* Initialize the stackprotector canary value.
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*
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-
* NOTE: this must only be called from functions that never return,
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+
* NOTE: this must only be called from functions that never return
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* and it must always be inlined.
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*
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* In addition, it should be called from a compilation unit for which
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* stack protector is disabled. Alternatively, the caller should not end
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* with a function call which gets tail-call optimized as that would
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* lead to checking a modified canary value.
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*/
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static __always_inline void boot_init_stack_canary(void)
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{
+8
arch/x86/kernel/smpboot.c
+8
arch/x86/kernel/smpboot.c
···
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wmb();
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cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
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+
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/*
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* Prevent tail call to cpu_startup_entry() because the stack protector
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* guard has been changed a couple of function calls up, in
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* boot_init_stack_canary() and must not be checked before tail calling
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* another function.
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+
*/
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+
prevent_tail_call_optimization();
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}
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/**
+1
arch/x86/xen/smp_pv.c
+1
arch/x86/xen/smp_pv.c
+6
include/linux/compiler.h
+6
include/linux/compiler.h
···
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/* &a[0] degrades to a pointer: a different type from an array */
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#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
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+
/*
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* This is needed in functions which generate the stack canary, see
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* arch/x86/kernel/smpboot.c::start_secondary() for an example.
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+
*/
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+
#define prevent_tail_call_optimization() mb()
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+
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#endif /* __LINUX_COMPILER_H */