From 7fbe6ac02485504b964b283aca62b36b4313ca79 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 24 Oct 2016 08:31:27 -0500 Subject: x86/unwind: Fix empty stack dereference in guess unwinder Vince Waver reported the following bug: WARNING: CPU: 0 PID: 21338 at arch/x86/mm/fault.c:435 vmalloc_fault+0x58/0x1f0 CPU: 0 PID: 21338 Comm: perf_fuzzer Not tainted 4.8.0+ #37 Hardware name: Hewlett-Packard HP Compaq Pro 6305 SFF/1850, BIOS K06 v02.57 08/16/2013 Call Trace: ? dump_stack+0x46/0x59 ? __warn+0xd5/0xee ? vmalloc_fault+0x58/0x1f0 ? __do_page_fault+0x6d/0x48e ? perf_log_throttle+0xa4/0xf4 ? trace_page_fault+0x22/0x30 ? __unwind_start+0x28/0x42 ? perf_callchain_kernel+0x75/0xac ? get_perf_callchain+0x13a/0x1f0 ? perf_callchain+0x6a/0x6c ? perf_prepare_sample+0x71/0x2eb ? perf_event_output_forward+0x1a/0x54 ? __default_send_IPI_shortcut+0x10/0x2d ? __perf_event_overflow+0xfb/0x167 ? x86_pmu_handle_irq+0x113/0x150 ? native_read_msr+0x6/0x34 ? perf_event_nmi_handler+0x22/0x39 ? perf_ibs_nmi_handler+0x4a/0x51 ? perf_event_nmi_handler+0x22/0x39 ? nmi_handle+0x4d/0xf0 ? perf_ibs_handle_irq+0x3d1/0x3d1 ? default_do_nmi+0x3c/0xd5 ? do_nmi+0x92/0x102 ? end_repeat_nmi+0x1a/0x1e ? entry_SYSCALL_64_after_swapgs+0x12/0x4a ? entry_SYSCALL_64_after_swapgs+0x12/0x4a ? entry_SYSCALL_64_after_swapgs+0x12/0x4a ^A4---[ end trace 632723104d47d31a ]--- BUG: stack guard page was hit at ffffc90008500000 (stack is ffffc900084fc000..ffffc900084fffff) kernel stack overflow (page fault): 0000 [#1] SMP ... The NMI hit in the entry code right after setting up the stack pointer from 'cpu_current_top_of_stack', so the kernel stack was empty. The 'guess' version of __unwind_start() attempted to dereference the "top of stack" pointer, which is not actually *on* the stack. Add a check in the guess unwinder to deal with an empty stack. (The frame pointer unwinder already has such a check.) Reported-by: Vince Weaver Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 7c7900f89770 ("x86/unwind: Add new unwind interface and implementations") Link: http://lkml.kernel.org/r/20161024133127.e5evgeebdbohnmpb@treble Signed-off-by: Ingo Molnar --- arch/x86/kernel/unwind_guess.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c index 9298993dc8b7..2d721e533cf4 100644 --- a/arch/x86/kernel/unwind_guess.c +++ b/arch/x86/kernel/unwind_guess.c @@ -47,7 +47,14 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, get_stack_info(first_frame, state->task, &state->stack_info, &state->stack_mask); - if (!__kernel_text_address(*first_frame)) + /* + * The caller can provide the address of the first frame directly + * (first_frame) or indirectly (regs->sp) to indicate which stack frame + * to start unwinding at. Skip ahead until we reach it. + */ + if (!unwind_done(state) && + (!on_stack(&state->stack_info, first_frame, sizeof(long)) || + !__kernel_text_address(*first_frame))) unwind_next_frame(state); } EXPORT_SYMBOL_GPL(__unwind_start); -- cgit v1.2.3 From a2209b742e6cf978b85d4f31a25a269c3d3b062b Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 24 Oct 2016 09:00:12 -0600 Subject: x86/build: Fix build with older GCC versions Older GCC (observed with 4.1.x) doesn't support -Wno-override-init and also doesn't ignore unknown -Wno-* options. Signed-off-by: Jan Beulich Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Valdis Kletnieks Cc: Valdis.Kletnieks@vt.edu Fixes: 5e44258d16 "x86/build: Reduce the W=1 warnings noise when compiling x86 syscall tables" Link: http://lkml.kernel.org/r/580E3E1C02000078001191C4@prv-mh.provo.novell.com Signed-off-by: Ingo Molnar --- arch/x86/entry/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile index 77f28ce9c646..9976fcecd17e 100644 --- a/arch/x86/entry/Makefile +++ b/arch/x86/entry/Makefile @@ -5,8 +5,8 @@ OBJECT_FILES_NON_STANDARD_entry_$(BITS).o := y OBJECT_FILES_NON_STANDARD_entry_64_compat.o := y -CFLAGS_syscall_64.o += -Wno-override-init -CFLAGS_syscall_32.o += -Wno-override-init +CFLAGS_syscall_64.o += $(call cc-option,-Wno-override-init,) +CFLAGS_syscall_32.o += $(call cc-option,-Wno-override-init,) obj-y := entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o obj-y += common.o -- cgit v1.2.3 From d320b9a5bd85f6178cc3ed8b0a1a9960f2b5bc7b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 24 Oct 2016 17:33:18 +0200 Subject: x86/quirks: Hide maybe-uninitialized warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gcc -Wmaybe-uninitialized detects that quirk_intel_brickland_xeon_ras_cap uses uninitialized data when CONFIG_PCI is not set: arch/x86/kernel/quirks.c: In function ‘quirk_intel_brickland_xeon_ras_cap’: arch/x86/kernel/quirks.c:641:13: error: ‘capid0’ is used uninitialized in this function [-Werror=uninitialized] However, the function is also not called in this configuration, so we can avoid the warning by moving the existing #ifdef to cover it as well. Signed-off-by: Arnd Bergmann Cc: Bjorn Helgaas Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20161024153325.2752428-1-arnd@arndb.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/quirks.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c index 51402a7e4ca6..0bee04d41bed 100644 --- a/arch/x86/kernel/quirks.c +++ b/arch/x86/kernel/quirks.c @@ -625,8 +625,6 @@ static void amd_disable_seq_and_redirect_scrub(struct pci_dev *dev) DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3, amd_disable_seq_and_redirect_scrub); -#endif - #if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE) #include #include @@ -657,3 +655,4 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, quirk_intel_brickland_xeon_ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, quirk_intel_brickland_xeon_ras_cap); DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2083, quirk_intel_purley_xeon_ras_cap); #endif +#endif -- cgit v1.2.3 From 5de0a8c0c240338cb5b73363b0673c6aa804bb1c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 24 Oct 2016 15:01:48 -0400 Subject: x86: Fix export for mcount and __fentry__ Commit 784d5699eddc5 ("x86: move exports to actual definitions") removed the EXPORT_SYMBOL(__fentry__) and EXPORT_SYMBOL(mcount) from x8664_ksyms_64.c, and added EXPORT_SYMBOL(function_hook) in mcount_64.S instead. The problem is that function_hook isn't a function at all, but a macro that is defined as either mcount or __fentry__ depending on the support from gcc. Originally, I thought this was a macro issue, like what __stringify() is used for. But the problem is a bit deeper. The Makefile.build has some magic that does post processing of files to create the CRC bindings. It does some searches for EXPORT_SYMBOL() and because it finds a macro name and not the actual functions, this causes function_hook not to be converted into mcount or __fentry__ and they are missed. Instead of adding more magic to Makefile.build, just add EXPORT_SYMBOL() for mcount and __fentry__ where the ifdef is used. Since this is assembly and not C, it doesn't require being set after the function is defined. Signed-off-by: Steven Rostedt Tested-by: Borislav Petkov Cc: Gabriel C Cc: Nicholas Piggin Cc: Al Viro Link: http://lkml.kernel.org/r/20161024150148.4f9d90e4@gandalf.local.home Signed-off-by: Thomas Gleixner --- arch/x86/kernel/mcount_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S index efe73aacf966..7b0d3da52fb4 100644 --- a/arch/x86/kernel/mcount_64.S +++ b/arch/x86/kernel/mcount_64.S @@ -18,8 +18,10 @@ #ifdef CC_USING_FENTRY # define function_hook __fentry__ +EXPORT_SYMBOL(__fentry__) #else # define function_hook mcount +EXPORT_SYMBOL(mcount) #endif /* All cases save the original rbp (8 bytes) */ @@ -295,7 +297,6 @@ trace: jmp fgraph_trace END(function_hook) #endif /* CONFIG_DYNAMIC_FTRACE */ -EXPORT_SYMBOL(function_hook) #endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER -- cgit v1.2.3 From 1c27f646b18fb56308dff82784ca61951bad0b48 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 27 Oct 2016 14:36:23 +0200 Subject: x86/microcode/AMD: Fix more fallout from CONFIG_RANDOMIZE_MEMORY=y We needed the physical address of the container in order to compute the offset within the relocated ramdisk. And we did this by doing __pa() on the virtual address. However, __pa() does checks whether the physical address is within PAGE_OFFSET and __START_KERNEL_map - see __phys_addr() - which fail if we have CONFIG_RANDOMIZE_MEMORY enabled: we feed a virtual address which *doesn't* have the randomization offset into a function which uses PAGE_OFFSET which *does* have that offset. This makes this check fire: VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x)); ^^^^^^ due to the randomization offset. The fix is as simple as using __pa_nodebug() because we do that randomization offset accounting later in that function ourselves. Reported-by: Bob Peterson Tested-by: Bob Peterson Signed-off-by: Borislav Petkov Cc: Andreas Gruenbacher Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Mel Gorman Cc: Peter Zijlstra Cc: Steven Whitehouse Cc: Thomas Gleixner Cc: linux-mm Cc: stable@vger.kernel.org # 4.9 Link: http://lkml.kernel.org/r/20161027123623.j2jri5bandimboff@pd.tnic Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/microcode/amd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 620ab06bcf45..017bda12caae 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -429,7 +429,7 @@ int __init save_microcode_in_initrd_amd(void) * We need the physical address of the container for both bitness since * boot_params.hdr.ramdisk_image is a physical address. */ - cont = __pa(container); + cont = __pa_nodebug(container); cont_va = container; #endif -- cgit v1.2.3