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8eed4e00a3
During memory error injection test on kernels >= v6.4, the kernel panics
like below. However, this issue couldn't be reproduced on kernels <= v6.3.
mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134
mce: [Hardware Error]: RIP 10:<ffffffff821b9776> {__get_user_nocheck_4+0x6/0x20}
mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86
mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490
mce: [Hardware Error]: Run the above through 'mcelog --ascii'
mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel
Kernel panic - not syncing: Fatal local machine check
The MCA code can recover from an in-kernel #MC if the fixup type is
EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to
access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT
the only thing that is raised for an in-kernel #MC is a panic.
ex_handler_uaccess() would warn if users gave a non-canonical addresses
(with bit 63 clear) to {get, put}_user(), which was unexpected.
Therefore, commit
b19b74bc99 ("x86/mm: Rework address range check in get_user() and put_user()")
replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user()
fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic.
Commit
6014bc2756 ("x86-64: make access_ok() independent of LAM")
added the check gp_fault_address_ok() right before the WARN_ONCE() in
ex_handler_uaccess() to not warn about non-canonical user addresses due
to LAM.
With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user()
exception fixups in order to be able to handle in-kernel MCEs correctly
again.
[ bp: Massage commit message. ]
Fixes: b19b74bc99 ("x86/mm: Rework address range check in get_user() and put_user()")
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20240129063842.61584-1-qiuxu.zhuo@intel.com
148 lines
3.1 KiB
ArmAsm
148 lines
3.1 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* __put_user functions.
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*
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* (C) Copyright 2005 Linus Torvalds
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* (C) Copyright 2005 Andi Kleen
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* (C) Copyright 2008 Glauber Costa
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*
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* These functions have a non-standard call interface
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* to make them more efficient, especially as they
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* return an error value in addition to the "real"
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* return value.
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*/
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#include <linux/export.h>
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#include <linux/linkage.h>
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#include <asm/thread_info.h>
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#include <asm/errno.h>
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#include <asm/asm.h>
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#include <asm/smap.h>
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/*
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* __put_user_X
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*
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* Inputs: %eax[:%edx] contains the data
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* %ecx contains the address
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*
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* Outputs: %ecx is error code (0 or -EFAULT)
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*
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* Clobbers: %ebx needed for task pointer
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*
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* These functions should not modify any other registers,
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* as they get called from within inline assembly.
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*/
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.macro check_range size:req
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.if IS_ENABLED(CONFIG_X86_64)
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mov %rcx, %rbx
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sar $63, %rbx
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or %rbx, %rcx
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.else
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cmp $TASK_SIZE_MAX-\size+1, %ecx
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jae .Lbad_put_user
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.endif
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.endm
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.text
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SYM_FUNC_START(__put_user_1)
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check_range size=1
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ASM_STAC
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1: movb %al,(%_ASM_CX)
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_1)
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EXPORT_SYMBOL(__put_user_1)
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SYM_FUNC_START(__put_user_nocheck_1)
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ASM_STAC
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2: movb %al,(%_ASM_CX)
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_nocheck_1)
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EXPORT_SYMBOL(__put_user_nocheck_1)
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SYM_FUNC_START(__put_user_2)
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check_range size=2
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ASM_STAC
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3: movw %ax,(%_ASM_CX)
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_2)
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EXPORT_SYMBOL(__put_user_2)
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SYM_FUNC_START(__put_user_nocheck_2)
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ASM_STAC
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4: movw %ax,(%_ASM_CX)
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_nocheck_2)
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EXPORT_SYMBOL(__put_user_nocheck_2)
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SYM_FUNC_START(__put_user_4)
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check_range size=4
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ASM_STAC
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5: movl %eax,(%_ASM_CX)
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_4)
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EXPORT_SYMBOL(__put_user_4)
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SYM_FUNC_START(__put_user_nocheck_4)
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ASM_STAC
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6: movl %eax,(%_ASM_CX)
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_nocheck_4)
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EXPORT_SYMBOL(__put_user_nocheck_4)
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SYM_FUNC_START(__put_user_8)
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check_range size=8
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ASM_STAC
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7: mov %_ASM_AX,(%_ASM_CX)
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#ifdef CONFIG_X86_32
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8: movl %edx,4(%_ASM_CX)
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#endif
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_8)
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EXPORT_SYMBOL(__put_user_8)
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SYM_FUNC_START(__put_user_nocheck_8)
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ASM_STAC
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9: mov %_ASM_AX,(%_ASM_CX)
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#ifdef CONFIG_X86_32
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10: movl %edx,4(%_ASM_CX)
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#endif
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xor %ecx,%ecx
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ASM_CLAC
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RET
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SYM_FUNC_END(__put_user_nocheck_8)
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EXPORT_SYMBOL(__put_user_nocheck_8)
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SYM_CODE_START_LOCAL(__put_user_handle_exception)
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ASM_CLAC
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.Lbad_put_user:
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movl $-EFAULT,%ecx
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RET
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SYM_CODE_END(__put_user_handle_exception)
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_ASM_EXTABLE_UA(1b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(2b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(3b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(4b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(5b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(6b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(7b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(9b, __put_user_handle_exception)
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#ifdef CONFIG_X86_32
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_ASM_EXTABLE_UA(8b, __put_user_handle_exception)
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_ASM_EXTABLE_UA(10b, __put_user_handle_exception)
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#endif
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