This is a note to let you know that I've just added the patch titled
x86/cpu_entry_area: Add debugstore entries to cpu_entry_area
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 10043e02db7f8a4161f76434931051e7d797a5f6 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx(a)linutronix.de>
Date: Mon, 4 Dec 2017 15:07:49 +0100
Subject: x86/cpu_entry_area: Add debugstore entries to cpu_entry_area
From: Thomas Gleixner <tglx(a)linutronix.de>
commit 10043e02db7f8a4161f76434931051e7d797a5f6 upstream.
The Intel PEBS/BTS debug store is a design trainwreck as it expects virtual
addresses which must be visible in any execution context.
So it is required to make these mappings visible to user space when kernel
page table isolation is active.
Provide enough room for the buffer mappings in the cpu_entry_area so the
buffers are available in the user space visible page tables.
At the point where the kernel side entry area is populated there is no
buffer available yet, but the kernel PMD must be populated. To achieve this
set the entries for these buffers to non present.
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Brian Gerst <brgerst(a)gmail.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Laight <David.Laight(a)aculab.com>
Cc: Denys Vlasenko <dvlasenk(a)redhat.com>
Cc: Eduardo Valentin <eduval(a)amazon.com>
Cc: Greg KH <gregkh(a)linuxfoundation.org>
Cc: H. Peter Anvin <hpa(a)zytor.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Will Deacon <will.deacon(a)arm.com>
Cc: aliguori(a)amazon.com
Cc: daniel.gruss(a)iaik.tugraz.at
Cc: hughd(a)google.com
Cc: keescook(a)google.com
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/events/intel/ds.c | 5 ++--
arch/x86/events/perf_event.h | 21 +------------------
arch/x86/include/asm/cpu_entry_area.h | 13 ++++++++++++
arch/x86/include/asm/intel_ds.h | 36 ++++++++++++++++++++++++++++++++++
arch/x86/mm/cpu_entry_area.c | 27 +++++++++++++++++++++++++
5 files changed, 81 insertions(+), 21 deletions(-)
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -8,11 +8,12 @@
#include "../perf_event.h"
+/* Waste a full page so it can be mapped into the cpu_entry_area */
+DEFINE_PER_CPU_PAGE_ALIGNED(struct debug_store, cpu_debug_store);
+
/* The size of a BTS record in bytes: */
#define BTS_RECORD_SIZE 24
-#define BTS_BUFFER_SIZE (PAGE_SIZE << 4)
-#define PEBS_BUFFER_SIZE (PAGE_SIZE << 4)
#define PEBS_FIXUP_SIZE PAGE_SIZE
/*
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -14,6 +14,8 @@
#include <linux/perf_event.h>
+#include <asm/intel_ds.h>
+
/* To enable MSR tracing please use the generic trace points. */
/*
@@ -77,8 +79,6 @@ struct amd_nb {
struct event_constraint event_constraints[X86_PMC_IDX_MAX];
};
-/* The maximal number of PEBS events: */
-#define MAX_PEBS_EVENTS 8
#define PEBS_COUNTER_MASK ((1ULL << MAX_PEBS_EVENTS) - 1)
/*
@@ -95,23 +95,6 @@ struct amd_nb {
PERF_SAMPLE_TRANSACTION | PERF_SAMPLE_PHYS_ADDR | \
PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER)
-/*
- * A debug store configuration.
- *
- * We only support architectures that use 64bit fields.
- */
-struct debug_store {
- u64 bts_buffer_base;
- u64 bts_index;
- u64 bts_absolute_maximum;
- u64 bts_interrupt_threshold;
- u64 pebs_buffer_base;
- u64 pebs_index;
- u64 pebs_absolute_maximum;
- u64 pebs_interrupt_threshold;
- u64 pebs_event_reset[MAX_PEBS_EVENTS];
-};
-
#define PEBS_REGS \
(PERF_REG_X86_AX | \
PERF_REG_X86_BX | \
--- a/arch/x86/include/asm/cpu_entry_area.h
+++ b/arch/x86/include/asm/cpu_entry_area.h
@@ -5,6 +5,7 @@
#include <linux/percpu-defs.h>
#include <asm/processor.h>
+#include <asm/intel_ds.h>
/*
* cpu_entry_area is a percpu region that contains things needed by the CPU
@@ -40,6 +41,18 @@ struct cpu_entry_area {
*/
char exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ];
#endif
+#ifdef CONFIG_CPU_SUP_INTEL
+ /*
+ * Per CPU debug store for Intel performance monitoring. Wastes a
+ * full page at the moment.
+ */
+ struct debug_store cpu_debug_store;
+ /*
+ * The actual PEBS/BTS buffers must be mapped to user space
+ * Reserve enough fixmap PTEs.
+ */
+ struct debug_store_buffers cpu_debug_buffers;
+#endif
};
#define CPU_ENTRY_AREA_SIZE (sizeof(struct cpu_entry_area))
--- /dev/null
+++ b/arch/x86/include/asm/intel_ds.h
@@ -0,0 +1,36 @@
+#ifndef _ASM_INTEL_DS_H
+#define _ASM_INTEL_DS_H
+
+#include <linux/percpu-defs.h>
+
+#define BTS_BUFFER_SIZE (PAGE_SIZE << 4)
+#define PEBS_BUFFER_SIZE (PAGE_SIZE << 4)
+
+/* The maximal number of PEBS events: */
+#define MAX_PEBS_EVENTS 8
+
+/*
+ * A debug store configuration.
+ *
+ * We only support architectures that use 64bit fields.
+ */
+struct debug_store {
+ u64 bts_buffer_base;
+ u64 bts_index;
+ u64 bts_absolute_maximum;
+ u64 bts_interrupt_threshold;
+ u64 pebs_buffer_base;
+ u64 pebs_index;
+ u64 pebs_absolute_maximum;
+ u64 pebs_interrupt_threshold;
+ u64 pebs_event_reset[MAX_PEBS_EVENTS];
+} __aligned(PAGE_SIZE);
+
+DECLARE_PER_CPU_PAGE_ALIGNED(struct debug_store, cpu_debug_store);
+
+struct debug_store_buffers {
+ char bts_buffer[BTS_BUFFER_SIZE];
+ char pebs_buffer[PEBS_BUFFER_SIZE];
+};
+
+#endif
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -38,6 +38,32 @@ cea_map_percpu_pages(void *cea_vaddr, vo
cea_set_pte(cea_vaddr, per_cpu_ptr_to_phys(ptr), prot);
}
+static void percpu_setup_debug_store(int cpu)
+{
+#ifdef CONFIG_CPU_SUP_INTEL
+ int npages;
+ void *cea;
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
+ return;
+
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_store;
+ npages = sizeof(struct debug_store) / PAGE_SIZE;
+ BUILD_BUG_ON(sizeof(struct debug_store) % PAGE_SIZE != 0);
+ cea_map_percpu_pages(cea, &per_cpu(cpu_debug_store, cpu), npages,
+ PAGE_KERNEL);
+
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers;
+ /*
+ * Force the population of PMDs for not yet allocated per cpu
+ * memory like debug store buffers.
+ */
+ npages = sizeof(struct debug_store_buffers) / PAGE_SIZE;
+ for (; npages; npages--, cea += PAGE_SIZE)
+ cea_set_pte(cea, 0, PAGE_NONE);
+#endif
+}
+
/* Setup the fixmap mappings only once per-processor */
static void __init setup_cpu_entry_area(int cpu)
{
@@ -109,6 +135,7 @@ static void __init setup_cpu_entry_area(
cea_set_pte(&get_cpu_entry_area(cpu)->entry_trampoline,
__pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
#endif
+ percpu_setup_debug_store(cpu);
}
static __init void setup_cpu_entry_area_ptes(void)
Patches currently in stable-queue which might be from tglx(a)linutronix.de are
queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch
queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch
queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch
queue-4.14/x86-mm-abstract-switching-cr3.patch
queue-4.14/x86-mm-optimize-restore_cr3.patch
queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch
queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch
queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch
queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch
queue-4.14/x86-mm-pti-share-entry-text-pmd.patch
queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch
queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch
queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch
queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch
queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch
queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch
queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch
queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch
queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch
queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch
queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch
queue-4.14/x86-mm-pti-add-kconfig.patch
queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch
queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch
queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch
queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch
queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch
queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch
queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch
queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch
queue-4.14/x86-mm-pti-populate-user-pgd.patch
queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch
This is a note to let you know that I've just added the patch titled
x86/cpufeatures: Add X86_BUG_CPU_INSECURE
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-cpufeatures-add-x86_bug_cpu_insecure.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From a89f040fa34ec9cd682aed98b8f04e3c47d998bd Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx(a)linutronix.de>
Date: Mon, 4 Dec 2017 15:07:33 +0100
Subject: x86/cpufeatures: Add X86_BUG_CPU_INSECURE
From: Thomas Gleixner <tglx(a)linutronix.de>
commit a89f040fa34ec9cd682aed98b8f04e3c47d998bd upstream.
Many x86 CPUs leak information to user space due to missing isolation of
user space and kernel space page tables. There are many well documented
ways to exploit that.
The upcoming software migitation of isolating the user and kernel space
page tables needs a misfeature flag so code can be made runtime
conditional.
Add the BUG bits which indicates that the CPU is affected and add a feature
bit which indicates that the software migitation is enabled.
Assume for now that _ALL_ x86 CPUs are affected by this. Exceptions can be
made later.
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Brian Gerst <brgerst(a)gmail.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Laight <David.Laight(a)aculab.com>
Cc: Denys Vlasenko <dvlasenk(a)redhat.com>
Cc: Eduardo Valentin <eduval(a)amazon.com>
Cc: Greg KH <gregkh(a)linuxfoundation.org>
Cc: H. Peter Anvin <hpa(a)zytor.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Will Deacon <will.deacon(a)arm.com>
Cc: aliguori(a)amazon.com
Cc: daniel.gruss(a)iaik.tugraz.at
Cc: hughd(a)google.com
Cc: keescook(a)google.com
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/cpufeatures.h | 3 ++-
arch/x86/include/asm/disabled-features.h | 8 +++++++-
arch/x86/kernel/cpu/common.c | 4 ++++
3 files changed, 13 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -201,7 +201,7 @@
#define X86_FEATURE_HW_PSTATE ( 7*32+ 8) /* AMD HW-PState */
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
-
+#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */
#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
#define X86_FEATURE_INTEL_PT ( 7*32+15) /* Intel Processor Trace */
#define X86_FEATURE_AVX512_4VNNIW ( 7*32+16) /* AVX-512 Neural Network Instructions */
@@ -340,5 +340,6 @@
#define X86_BUG_SWAPGS_FENCE X86_BUG(11) /* SWAPGS without input dep on GS */
#define X86_BUG_MONITOR X86_BUG(12) /* IPI required to wake up remote CPU */
#define X86_BUG_AMD_E400 X86_BUG(13) /* CPU is among the affected by Erratum 400 */
+#define X86_BUG_CPU_INSECURE X86_BUG(14) /* CPU is insecure and needs kernel page table isolation */
#endif /* _ASM_X86_CPUFEATURES_H */
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -44,6 +44,12 @@
# define DISABLE_LA57 (1<<(X86_FEATURE_LA57 & 31))
#endif
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+# define DISABLE_PTI 0
+#else
+# define DISABLE_PTI (1 << (X86_FEATURE_PTI & 31))
+#endif
+
/*
* Make sure to add features to the correct mask
*/
@@ -54,7 +60,7 @@
#define DISABLED_MASK4 (DISABLE_PCID)
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
-#define DISABLED_MASK7 0
+#define DISABLED_MASK7 (DISABLE_PTI)
#define DISABLED_MASK8 0
#define DISABLED_MASK9 (DISABLE_MPX)
#define DISABLED_MASK10 0
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -898,6 +898,10 @@ static void __init early_identify_cpu(st
}
setup_force_cpu_cap(X86_FEATURE_ALWAYS);
+
+ /* Assume for now that ALL x86 CPUs are insecure */
+ setup_force_cpu_bug(X86_BUG_CPU_INSECURE);
+
fpu__init_system(c);
#ifdef CONFIG_X86_32
Patches currently in stable-queue which might be from tglx(a)linutronix.de are
queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch
Hello,
4.14.9 fails to boot if CONFIG_MCORE2 is enabled and when compiled with
gcc 6+. More details in the following bug reports:
https://bugzilla.kernel.org/show_bug.cgi?id=198263https://bugs.gentoo.org/642268
I bisected it to the commit below:
$ git bisect good
2bc9fa0beaf10206a778f02e9e5cb62f50345b1a is the first bad commit
commit 2bc9fa0beaf10206a778f02e9e5cb62f50345b1a
Author: Andy Lutomirski <luto(a)kernel.org>
Date: Mon Dec 4 15:07:23 2017 +0100
x86/entry/64: Use a per-CPU trampoline stack for IDT entries
commit 7f2590a110b837af5679d08fc25c6227c5a8c497 upstream.
Historically, IDT entries from usermode have always gone directly
to the running task's kernel stack. Rearrange it so that we enter
on
a per-CPU trampoline stack and then manually switch to the task's
stack.
This touches a couple of extra cachelines, but it gives us a chance
to run some code before we touch the kernel stack.
The asm isn't exactly beautiful, but I think that fully refactoring
it can wait.
Signed-off-by: Andy Lutomirski <luto(a)kernel.org>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Reviewed-by: Borislav Petkov <bp(a)suse.de>
Reviewed-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Borislav Petkov <bpetkov(a)suse.de>
Cc: Brian Gerst <brgerst(a)gmail.com>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Laight <David.Laight(a)aculab.com>
Cc: Denys Vlasenko <dvlasenk(a)redhat.com>
Cc: Eduardo Valentin <eduval(a)amazon.com>
Cc: Greg KH <gregkh(a)linuxfoundation.org>
Cc: H. Peter Anvin <hpa(a)zytor.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Will Deacon <will.deacon(a)arm.com>
Cc: aliguori(a)amazon.com
Cc: daniel.gruss(a)iaik.tugraz.at
Cc: hughd(a)google.com
Cc: keescook(a)google.com
Link: https://lkml.kernel.org/r/20171204150606.225330557@linutronix
.de
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
:040000 040000 275d4746936a9e521a2b5041856f7dc1d1820dc6
8f8e869fd59c3dd781dceffa76e53e41d733a0cf M arch
$ git bisect log
git bisect start
# bad: [dad5c1402c570cd07a80113784bc20a7f930c8ae] Linux 4.14.9
git bisect bad dad5c1402c570cd07a80113784bc20a7f930c8ae
# good: [7b3775017f4e6b87dfd2c7f63d1eaf057948f31d] Linux 4.14.8
git bisect good 7b3775017f4e6b87dfd2c7f63d1eaf057948f31d
# good: [d120cd749ef9770ee98b708a83b49547dcf1c0e1] x86/entry/64:
Separate cpu_current_top_of_stack from TSS.sp0
git bisect good d120cd749ef9770ee98b708a83b49547dcf1c0e1
# bad: [97f41b41c432e5a80c91445d92c2f4b729984d36] powerpc/xmon: Avoid
tripping SMP hardlockup watchdog
git bisect bad 97f41b41c432e5a80c91445d92c2f4b729984d36
# bad: [bfd66a406fe7e590055c1d6714adc697f18664c8] PCI: Avoid bus reset
if bridge itself is broken
git bisect bad bfd66a406fe7e590055c1d6714adc697f18664c8
# bad: [8388d287e361a2fd0a39bece30a736d692d5c3d8] x86/cpufeatures: Make
CPU bugs sticky
git bisect bad 8388d287e361a2fd0a39bece30a736d692d5c3d8
# bad: [bb568391775d4a840992e2d2493f39d6e86401e3] x86/entry/64: Move
the IST stacks into struct cpu_entry_area
git bisect bad bb568391775d4a840992e2d2493f39d6e86401e3
# bad: [2bc9fa0beaf10206a778f02e9e5cb62f50345b1a] x86/entry/64: Use a
per-CPU trampoline stack for IDT entries
git bisect bad 2bc9fa0beaf10206a778f02e9e5cb62f50345b1a
# good: [c3dbef1bd0f7eb09daf49409ea533aa1b0eeb82e] x86/espfix/64: Stop
assuming that pt_regs is on the entry stack
git bisect good c3dbef1bd0f7eb09daf49409ea533aa1b0eeb82e
# first bad commit: [2bc9fa0beaf10206a778f02e9e5cb62f50345b1a]
x86/entry/64: Use a per-CPU trampoline stack for IDT entries
This is a note to let you know that I've just added the patch titled
tracing: Fix possible double free on failure of allocating trace buffer
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 4397f04575c44e1440ec2e49b6302785c95fd2f8 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt(a)goodmis.org>
Date: Tue, 26 Dec 2017 20:07:34 -0500
Subject: tracing: Fix possible double free on failure of allocating trace buffer
From: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
commit 4397f04575c44e1440ec2e49b6302785c95fd2f8 upstream.
Jing Xia and Chunyan Zhang reported that on failing to allocate part of the
tracing buffer, memory is freed, but the pointers that point to them are not
initialized back to NULL, and later paths may try to free the freed memory
again. Jing and Chunyan fixed one of the locations that does this, but
missed a spot.
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Reported-by: Jing Xia <jing.xia(a)spreadtrum.com>
Reported-by: Chunyan Zhang <chunyan.zhang(a)spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
kernel/trace/trace.c | 1 +
1 file changed, 1 insertion(+)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6955,6 +6955,7 @@ allocate_trace_buffer(struct trace_array
buf->data = alloc_percpu(struct trace_array_cpu);
if (!buf->data) {
ring_buffer_free(buf->buffer);
+ buf->buffer = NULL;
return -ENOMEM;
}
Patches currently in stable-queue which might be from rostedt(a)goodmis.org are
queue-4.9/tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch
queue-4.9/tracing-remove-extra-zeroing-out-of-the-ring-buffer-page.patch
queue-4.9/tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch
This is a note to let you know that I've just added the patch titled
tracing: Remove extra zeroing out of the ring buffer page
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
tracing-remove-extra-zeroing-out-of-the-ring-buffer-page.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 6b7e633fe9c24682df550e5311f47fb524701586 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt(a)goodmis.org>
Date: Fri, 22 Dec 2017 20:38:57 -0500
Subject: tracing: Remove extra zeroing out of the ring buffer page
From: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
commit 6b7e633fe9c24682df550e5311f47fb524701586 upstream.
The ring_buffer_read_page() takes care of zeroing out any extra data in the
page that it returns. There's no need to zero it out again from the
consumer. It was removed from one consumer of this function, but
read_buffers_splice_read() did not remove it, and worse, it contained a
nasty bug because of it.
Fixes: 2711ca237a084 ("ring-buffer: Move zeroing out excess in page to ring buffer code")
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
kernel/trace/trace.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6181,7 +6181,7 @@ tracing_buffers_splice_read(struct file
.spd_release = buffer_spd_release,
};
struct buffer_ref *ref;
- int entries, size, i;
+ int entries, i;
ssize_t ret = 0;
#ifdef CONFIG_TRACER_MAX_TRACE
@@ -6232,14 +6232,6 @@ tracing_buffers_splice_read(struct file
break;
}
- /*
- * zero out any left over data, this is going to
- * user land.
- */
- size = ring_buffer_page_len(ref->page);
- if (size < PAGE_SIZE)
- memset(ref->page + size, 0, PAGE_SIZE - size);
-
page = virt_to_page(ref->page);
spd.pages[i] = page;
Patches currently in stable-queue which might be from rostedt(a)goodmis.org are
queue-4.9/tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch
queue-4.9/tracing-remove-extra-zeroing-out-of-the-ring-buffer-page.patch
queue-4.9/tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch
This is a note to let you know that I've just added the patch titled
tracing: Fix crash when it fails to alloc ring buffer
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5 Mon Sep 17 00:00:00 2001
From: Jing Xia <jing.xia(a)spreadtrum.com>
Date: Tue, 26 Dec 2017 15:12:53 +0800
Subject: tracing: Fix crash when it fails to alloc ring buffer
From: Jing Xia <jing.xia(a)spreadtrum.com>
commit 24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5 upstream.
Double free of the ring buffer happens when it fails to alloc new
ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured.
The root cause is that the pointer is not set to NULL after the buffer
is freed in allocate_trace_buffers(), and the freeing of the ring
buffer is invoked again later if the pointer is not equal to Null,
as:
instance_mkdir()
|-allocate_trace_buffers()
|-allocate_trace_buffer(tr, &tr->trace_buffer...)
|-allocate_trace_buffer(tr, &tr->max_buffer...)
// allocate fail(-ENOMEM),first free
// and the buffer pointer is not set to null
|-ring_buffer_free(tr->trace_buffer.buffer)
// out_free_tr
|-free_trace_buffers()
|-free_trace_buffer(&tr->trace_buffer);
//if trace_buffer is not null, free again
|-ring_buffer_free(buf->buffer)
|-rb_free_cpu_buffer(buffer->buffers[cpu])
// ring_buffer_per_cpu is null, and
// crash in ring_buffer_per_cpu->pages
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Signed-off-by: Jing Xia <jing.xia(a)spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang(a)spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
kernel/trace/trace.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6979,7 +6979,9 @@ static int allocate_trace_buffers(struct
allocate_snapshot ? size : 1);
if (WARN_ON(ret)) {
ring_buffer_free(tr->trace_buffer.buffer);
+ tr->trace_buffer.buffer = NULL;
free_percpu(tr->trace_buffer.data);
+ tr->trace_buffer.data = NULL;
return -ENOMEM;
}
tr->allocated_snapshot = allocate_snapshot;
Patches currently in stable-queue which might be from jing.xia(a)spreadtrum.com are
queue-4.9/tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch
queue-4.9/tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch
This is a note to let you know that I've just added the patch titled
tracing: Fix possible double free on failure of allocating trace buffer
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 4397f04575c44e1440ec2e49b6302785c95fd2f8 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt(a)goodmis.org>
Date: Tue, 26 Dec 2017 20:07:34 -0500
Subject: tracing: Fix possible double free on failure of allocating trace buffer
From: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
commit 4397f04575c44e1440ec2e49b6302785c95fd2f8 upstream.
Jing Xia and Chunyan Zhang reported that on failing to allocate part of the
tracing buffer, memory is freed, but the pointers that point to them are not
initialized back to NULL, and later paths may try to free the freed memory
again. Jing and Chunyan fixed one of the locations that does this, but
missed a spot.
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Reported-by: Jing Xia <jing.xia(a)spreadtrum.com>
Reported-by: Chunyan Zhang <chunyan.zhang(a)spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
kernel/trace/trace.c | 1 +
1 file changed, 1 insertion(+)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6531,6 +6531,7 @@ allocate_trace_buffer(struct trace_array
buf->data = alloc_percpu(struct trace_array_cpu);
if (!buf->data) {
ring_buffer_free(buf->buffer);
+ buf->buffer = NULL;
return -ENOMEM;
}
Patches currently in stable-queue which might be from rostedt(a)goodmis.org are
queue-4.4/tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch
queue-4.4/tracing-remove-extra-zeroing-out-of-the-ring-buffer-page.patch
queue-4.4/tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch