6.7-stable review patch. If anyone has any objections, please let me know.
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From: Qiuxu Zhuo qiuxu.zhuo@intel.com
commit 8eed4e00a370b37b4e5985ed983dccedd555ea9d upstream.
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
b19b74bc99b1 ("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
6014bc27561f ("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: b19b74bc99b1 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/lib/getuser.S | 24 ++++++++++++------------ arch/x86/lib/putuser.S | 20 ++++++++++---------- 2 files changed, 22 insertions(+), 22 deletions(-)
--- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -163,23 +163,23 @@ SYM_CODE_END(__get_user_8_handle_excepti #endif
/* get_user */ - _ASM_EXTABLE(1b, __get_user_handle_exception) - _ASM_EXTABLE(2b, __get_user_handle_exception) - _ASM_EXTABLE(3b, __get_user_handle_exception) + _ASM_EXTABLE_UA(1b, __get_user_handle_exception) + _ASM_EXTABLE_UA(2b, __get_user_handle_exception) + _ASM_EXTABLE_UA(3b, __get_user_handle_exception) #ifdef CONFIG_X86_64 - _ASM_EXTABLE(4b, __get_user_handle_exception) + _ASM_EXTABLE_UA(4b, __get_user_handle_exception) #else - _ASM_EXTABLE(4b, __get_user_8_handle_exception) - _ASM_EXTABLE(5b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(4b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(5b, __get_user_8_handle_exception) #endif
/* __get_user */ - _ASM_EXTABLE(6b, __get_user_handle_exception) - _ASM_EXTABLE(7b, __get_user_handle_exception) - _ASM_EXTABLE(8b, __get_user_handle_exception) + _ASM_EXTABLE_UA(6b, __get_user_handle_exception) + _ASM_EXTABLE_UA(7b, __get_user_handle_exception) + _ASM_EXTABLE_UA(8b, __get_user_handle_exception) #ifdef CONFIG_X86_64 - _ASM_EXTABLE(9b, __get_user_handle_exception) + _ASM_EXTABLE_UA(9b, __get_user_handle_exception) #else - _ASM_EXTABLE(9b, __get_user_8_handle_exception) - _ASM_EXTABLE(10b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(9b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(10b, __get_user_8_handle_exception) #endif --- a/arch/x86/lib/putuser.S +++ b/arch/x86/lib/putuser.S @@ -133,15 +133,15 @@ SYM_CODE_START_LOCAL(__put_user_handle_e RET SYM_CODE_END(__put_user_handle_exception)
- _ASM_EXTABLE(1b, __put_user_handle_exception) - _ASM_EXTABLE(2b, __put_user_handle_exception) - _ASM_EXTABLE(3b, __put_user_handle_exception) - _ASM_EXTABLE(4b, __put_user_handle_exception) - _ASM_EXTABLE(5b, __put_user_handle_exception) - _ASM_EXTABLE(6b, __put_user_handle_exception) - _ASM_EXTABLE(7b, __put_user_handle_exception) - _ASM_EXTABLE(9b, __put_user_handle_exception) + _ASM_EXTABLE_UA(1b, __put_user_handle_exception) + _ASM_EXTABLE_UA(2b, __put_user_handle_exception) + _ASM_EXTABLE_UA(3b, __put_user_handle_exception) + _ASM_EXTABLE_UA(4b, __put_user_handle_exception) + _ASM_EXTABLE_UA(5b, __put_user_handle_exception) + _ASM_EXTABLE_UA(6b, __put_user_handle_exception) + _ASM_EXTABLE_UA(7b, __put_user_handle_exception) + _ASM_EXTABLE_UA(9b, __put_user_handle_exception) #ifdef CONFIG_X86_32 - _ASM_EXTABLE(8b, __put_user_handle_exception) - _ASM_EXTABLE(10b, __put_user_handle_exception) + _ASM_EXTABLE_UA(8b, __put_user_handle_exception) + _ASM_EXTABLE_UA(10b, __put_user_handle_exception) #endif