kernel.git/arch/x86/kernel/cpu/mcheck, branch linux-4.16.y

x86/MCE: Fix stack out-of-bounds write in mce-inject.c: Flags_read()

2018-06-25T23:53:59Z

commit 985c78d3ff8e9c74450fa2bb08eb55e680d999ca upstream. Each of the strings that we want to put into the buf[MAX_FLAG_OPT_SIZE] in flags_read() is two characters long. But the sprintf() adds a trailing newline and will add a terminating NUL byte. So MAX_FLAG_OPT_SIZE needs to be 4. sprintf() calls vsnprintf() and *that* does return: " * The return value is the number of characters which would * be generated for the given input, excluding the trailing * '\0', as per ISO C99." Note the "excluding". Reported-by: Dmitry Vyukov Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Cc: linux-edac Link: http://lkml.kernel.org/r/20180427163707.ktaiysvbk3yhk4wm@agluck-desk Signed-off-by: Greg Kroah-Hartman

x86/MCE/AMD: Cache SMCA MISC block addresses

2018-06-05T09:46:09Z

commit 78ce241099bb363b19dbd0245442e66c8de8f567 upstream. ... into a global, two-dimensional array and service subsequent reads from that cache to avoid rdmsr_on_cpu() calls during CPU hotplug (IPIs with IRQs disabled). In addition, this fixes a KASAN slab-out-of-bounds read due to wrong usage of the bank->blocks pointer. Fixes: 27bd59502702 ("x86/mce/AMD: Get address from already initialized block") Reported-by: Johannes Hirte Tested-by: Johannes Hirte Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: Yazen Ghannam Link: http://lkml.kernel.org/r/20180414004230.GA2033@probook Signed-off-by: Greg Kroah-Hartman

x86/mce/AMD: Carve out SMCA get_block_address() code

2018-06-05T09:46:09Z

commit 8a331f4a0863bea758561c921b94b4d28f7c4029 upstream. Carve out the SMCA code in get_block_address() into a separate helper function. No functional change. Signed-off-by: Yazen Ghannam [ Save an indentation level. ] Signed-off-by: Borislav Petkov Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20180215210943.11530-4-Yazen.Ghannam@amd.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/mce/AMD: Get address from already initialized block

2018-04-19T06:54:07Z

commit 27bd59502702fe51d9eb00450a75b727ec6bfcb4 upstream. The block address is saved after the block is initialized when threshold_init_device() is called. Use the saved block address, if available, rather than trying to rediscover it. This will avoid a call trace, when resuming from suspend, due to the rdmsr_safe_on_cpu() call in get_block_address(). The rdmsr_safe_on_cpu() call issues an IPI but we're running with interrupts disabled. This triggers: WARNING: CPU: 0 PID: 11523 at kernel/smp.c:291 smp_call_function_single+0xdc/0xe0 Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: # 4.14.x Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20180221101900.10326-8-bp@alien8.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/mce/AMD, EDAC/mce_amd: Enumerate Reserved SMCA bank type

2018-04-19T06:54:07Z

commit 68627a697c195937672ce07683094c72b1174786 upstream. Currently, bank 4 is reserved on Fam17h, so we chose not to initialize bank 4 in the smca_banks array. This means that when we check if a bank is initialized, like during boot or resume, we will see that bank 4 is not initialized and try to initialize it. This will cause a call trace, when resuming from suspend, due to rdmsr_*on_cpu() calls in the init path. The rdmsr_*on_cpu() calls issue an IPI but we're running with interrupts disabled. This triggers: WARNING: CPU: 0 PID: 11523 at kernel/smp.c:291 smp_call_function_single+0xdc/0xe0 ... Reserved banks will be read-as-zero, so their MCA_IPID register will be zero. So, like the smca_banks array, the threshold_banks array will not have an entry for a reserved bank since all its MCA_MISC* registers will be zero. Enumerate a "Reserved" bank type that matches on a HWID_MCATYPE of 0,0. Use the "Reserved" type when checking if a bank is reserved. It's possible that other bank numbers may be reserved on future systems. Don't try to find the block address on reserved banks. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: # 4.14.x Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20180221101900.10326-7-bp@alien8.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/mce/AMD: Pass the bank number to smca_get_bank_type()

2018-04-19T06:54:07Z

commit e5d6a126d4c473499f354254a15ca0c2d8c84ca3 upstream. Pass the bank number to smca_get_bank_type() since that's all we need. Also, we should compare the bank number to MAX_NR_BANKS (size of the smca_banks array) not the number of bank types. Bank types are reused for multiple banks, so the number of types can be different from the number of banks in a system and thus we could return an invalid bank type. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: # 4.14.x Cc: # 4.14.x: 11cf887728a3 x86/MCE/AMD: Define a function to get SMCA bank type Cc: # 4.14.x: c6708d50f166 x86/MCE: Report only DRAM ECC as memory errors on AMD systems Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20180221101900.10326-6-bp@alien8.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/MCE: Serialize sysfs changes

2018-03-08T14:36:27Z

The check_interval file in /sys/devices/system/machinecheck/machinecheck directory is a global timer value for MCE polling. If it is changed by one CPU, mce_restart() broadcasts the event to other CPUs to delete and restart the MCE polling timer and __mcheck_cpu_init_timer() reinitializes the mce_timer variable. If more than one CPU writes a specific value to the check_interval file concurrently, mce_timer is not protected from such concurrent accesses and all kinds of explosions happen. Since only root can write to those sysfs variables, the issue is not a big deal security-wise. However, concurrent writes to these configuration variables is void of reason so the proper thing to do is to serialize the access with a mutex. Boris: - Make store_int_with_restart() use device_store_ulong() to filter out negative intervals - Limit min interval to 1 second - Correct locking - Massage commit message Signed-off-by: Seunghun Han Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: Tony Luck Cc: linux-edac Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20180302202706.9434-1-kkamagui@gmail.com

x86/MCE: Save microcode revision in machine check records

2018-03-08T14:34:49Z

Updating microcode used to be relatively rare. Now that it has become more common we should save the microcode version in a machine check record to make sure that those people looking at the error have this important information bundled with the rest of the logged information. [ Borislav: Simplify a bit. ] Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: Yazen Ghannam Cc: linux-edac Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20180301233449.24311-1-tony.luck@intel.com

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-02-15T01:31:51Z

Pull x86 fixes from Ingo Molnar: "Misc fixes all across the map: - /proc/kcore vsyscall related fixes - LTO fix - build warning fix - CPU hotplug fix - Kconfig NR_CPUS cleanups - cpu_has() cleanups/robustification - .gitignore fix - memory-failure unmapping fix - UV platform fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages x86/error_inject: Make just_return_func() globally visible x86/platform/UV: Fix GAM Range Table entries less than 1GB x86/build: Add arch/x86/tools/insn_decoder_test to .gitignore x86/smpboot: Fix uncore_pci_remove() indexing bug when hot-removing a physical CPU x86/mm/kcore: Add vsyscall page to /proc/kcore conditionally vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page x86/Kconfig: Further simplify the NR_CPUS config x86/Kconfig: Simplify NR_CPUS config x86/MCE: Fix build warning introduced by "x86: do not use print_symbol()" x86/cpufeature: Update _static_cpu_has() to use all named variables x86/cpufeature: Reindent _static_cpu_has()

x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages

2018-02-13T15:25:06Z

In the following commit: ce0fa3e56ad2 ("x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages") ... we added code to memory_failure() to unmap the page from the kernel 1:1 virtual address space to avoid speculative access to the page logging additional errors. But memory_failure() may not always succeed in taking the page offline, especially if the page belongs to the kernel. This can happen if there are too many corrected errors on a page and either mcelog(8) or drivers/ras/cec.c asks to take a page offline. Since we remove the 1:1 mapping early in memory_failure(), we can end up with the page unmapped, but still in use. On the next access the kernel crashes :-( There are also various debug paths that call memory_failure() to simulate occurrence of an error. Since there is no actual error in memory, we don't need to map out the page for those cases. Revert most of the previous attempt and keep the solution local to arch/x86/kernel/cpu/mcheck/mce.c. Unmap the page only when: 1) there is a real error 2) memory_failure() succeeds. All of this only applies to 64-bit systems. 32-bit kernel doesn't map all of memory into kernel space. It isn't worth adding the code to unmap the piece that is mapped because nobody would run a 32-bit kernel on a machine that has recoverable machine checks. Signed-off-by: Tony Luck Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Cc: Denys Vlasenko Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Naoya Horiguchi Cc: Peter Zijlstra Cc: Robert (Persistent Memory) Cc: Thomas Gleixner Cc: linux-mm@kvack.org Cc: stable@vger.kernel.org #v4.14 Fixes: ce0fa3e56ad2 ("x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages") Signed-off-by: Ingo Molnar