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dc912c3035
linux/arch/x86/kernel
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Steven Rostedt (VMware) dc912c3035 x86/ftrace: Fix ebp in ftrace_regs_caller that screws up unwinder 
Fengguang Wu's zero day bot triggered a stack unwinder dump. This can
be easily triggered when CONFIG_FRAME_POINTERS is enabled and -mfentry
is in use on x86_32.

 ># cd /sys/kernel/debug/tracing
 ># echo 'p:schedule schedule' > kprobe_events
 ># echo stacktrace > events/kprobes/schedule/trigger

This is because the code that implemented fentry in the ftrace_regs_caller
tried to use the least amount of #ifdefs, and modified ebp when
CC_USE_FENTRY was defined to point to the parent ip as it does when
CC_USE_FENTRY is not defined. But when CONFIG_FRAME_POINTERS is set, it
corrupts the ebp register for this frame while doing the tracing.

NOTE, it does not corrupt ebp in any other way. It is just a bad frame
pointer when calling into the tracing infrastructure. The original ebp is
restored before returning from the fentry call. But if a stack trace is
performed inside the tracing, the unwinder will notice the bad ebp.

Instead of toying with ebp with CC_USING_FENTRY, just slap the parent ip
into the second parameter (%edx), and have an #else that does it the
original way.

The unwinder will unfortunately miss the function being traced, as the
stack frame is not set up yet for it, as it is for x86_64. But fixing that
is a bit more complex and did not work before anyway.

This has been tested with and without FRAME_POINTERS being set while using
-mfentry, as well as using an older compiler that uses mcount.

Analyzed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Fixes: 644e0e8dc7 ("x86/ftrace: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set")
Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lists.01.org/pipermail/lkp/2017-April/006165.html
Link: http://lkml.kernel.org/r/20170420172236.7af7f6e5@gandalf.local.home
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-21 09:48:16 +02:00
..
acpi x86/acpi: Restore the order of CPU IDs 2017-03-11 14:41:19 +01:00
apic x86/acpi: Restore the order of CPU IDs 2017-03-11 14:41:19 +01:00
cpu x86/intel_rdt: Put group node in rdtgroup_kn_unlock 2017-03-14 21:51:58 +01:00
fpu sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
kprobes Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-07 14:38:16 -08:00
.gitignore
alternative.c x86/alternatives: Do not use sync_core() to serialize I$ 2016-12-20 09:36:42 +01:00
amd_gart_64.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
amd_nb.c x86/amd_nb: Add SMN and Indirect Data Fabric access for AMD Fam17h 2016-11-16 20:46:38 +01:00
apb_timer.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
aperture_64.c param: convert some "on"/"off" users to strtobool 2016-03-17 15:09:34 -07:00
apm_32.c sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h> 2017-03-02 08:42:39 +01:00
asm-offsets_32.c sched/x86: Rewrite the switch_to() code 2016-08-24 12:31:41 +02:00
asm-offsets_64.c x86/kvm: Provide optimized version of vcpu_is_preempted() for x86-64 2017-02-21 12:48:35 +01:00
asm-offsets.c efi: Get and store the secure boot status 2017-02-07 10:42:10 +01:00
audit_64.c
bootflag.c
check.c
cpuid.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:25:04 -08:00
crash_dump_32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
crash_dump_64.c
crash.c kexec_file: Change kexec_add_buffer to take kexec_buf as argument. 2016-11-30 23:14:59 +11:00
devicetree.c x86/cpufeature: Replace cpu_has_apic with boot_cpu_has() usage 2016-04-13 11:37:41 +02:00
doublefault.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
dumpstack_32.c x86/debug: Implement __WARN() using UD0 2017-03-27 10:20:28 +02:00
dumpstack_64.c x86/debug: Implement __WARN() using UD0 2017-03-27 10:20:28 +02:00
dumpstack.c x86/unwind: Ensure stack pointer is aligned 2017-04-18 10:30:23 +02:00
e820.c x86/e820/32: Fix e820_search_gap() error handling on x86-32 2017-01-12 09:40:06 +01:00
early_printk.c x86: Fix misspellings in comments 2016-02-24 08:44:58 +01:00
early-quirks.c Merge tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux 2016-10-11 18:12:22 -07:00
ebda.c x86/boot: Simplify EBDA-vs-BIOS reservation logic 2016-07-22 11:46:01 +02:00
espfix_64.c x86: get rid of superfluous __GFP_REPEAT 2016-06-24 17:23:52 -07:00
ftrace_32.S x86/ftrace: Fix ebp in ftrace_regs_caller that screws up unwinder 2017-04-21 09:48:16 +02:00
ftrace_64.S x86/ftrace: Use Makefile logic instead of #ifdef for compiling ftrace_*.o 2017-03-24 10:14:08 +01:00
ftrace.c scripts/spelling.txt: add "disble(d)" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
head32.c x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C 2017-01-06 08:39:26 +01:00
head64.c x86/kasan: Fix boot with KASAN=y and PROFILE_ANNOTATED_BRANCHES=y 2017-03-14 00:00:55 +01:00
head_32.S x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C 2017-01-06 08:39:26 +01:00
head_64.S x86/boot/64: Push correct start_cpu() return address 2016-12-14 08:48:05 +01:00
hpet.c x86/hpet: Prevent might sleep splat on resume 2017-03-02 09:33:47 +01:00
hw_breakpoint.c x86/kernel: Audit and remove any unnecessary uses of module.h 2016-07-14 15:06:41 +02:00
i8237.c
i8253.c x86/kernel: Audit and remove any unnecessary uses of module.h 2016-07-14 15:06:41 +02:00
i8259.c x86/irq: Probe for PIC presence before allocating descs for legacy IRQs 2015-11-07 10:37:37 +01:00
io_delay.c x86/kernel: Audit and remove any unnecessary uses of module.h 2016-07-14 15:06:41 +02:00
ioport.c Second batch of KVM changes for 4.11 merge window 2017-03-04 11:36:19 -08:00
irq_32.c x86/kernel: Audit and remove any unnecessary uses of module.h 2016-07-14 15:06:41 +02:00
irq_64.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
irq_work.c x86/irq, trace: Add __irq_entry annotation to x86's platform IRQ handlers 2017-01-05 08:58:49 +01:00
irq.c x86/irq, trace: Add __irq_entry annotation to x86's platform IRQ handlers 2017-01-05 08:58:49 +01:00
irqinit.c
itmt.c sched/x86: Remove unnecessary TBM3 check to update topology 2017-01-19 08:42:37 +01:00
jump_label.c locking/jump_labels: Update bug_at() boot message 2017-01-12 09:43:07 +01:00
kdebugfs.c x86/kdebugfs: Move boot params hierarchy under (debugfs)/x86/ 2017-03-01 09:57:02 +01:00
kexec-bzimage64.c kexec_file: Change kexec_add_buffer to take kexec_buf as argument. 2016-11-30 23:14:59 +11:00
kgdb.c sched/x86: Add 'struct inactive_task_frame' to better document the sleeping task stack frame 2016-08-24 12:27:41 +02:00
ksysfs.c x86: Apply more __ro_after_init and const 2016-08-10 14:55:05 +02:00
kvm.c 4.11 is going to be a relatively large release for KVM, with a little over 2017-02-22 18:22:53 -08:00
kvmclock.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
ldt.c Merge branch 'akpm' (patches from Andrew) 2016-12-12 20:50:02 -08:00
livepatch.c livepatch/x86: apply alternatives and paravirt patches after relocations 2016-08-18 23:41:55 +02:00
machine_kexec_32.c
machine_kexec_64.c kexec, x86/purgatory: Unbreak it and clean it up 2017-03-10 20:55:09 +01:00
Makefile x86/ftrace: Use Makefile logic instead of #ifdef for compiling ftrace_*.o 2017-03-24 10:14:08 +01:00
mmconf-fam10h_64.c
module.c x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
mpparse.c x86/mm/numa: Open code function early_get_boot_cpu_id() 2016-08-15 08:51:54 +02:00
msr.c x86/msr: Remove bogus cleanup from the error path 2016-12-25 10:47:41 +01:00
nmi_selftest.c
nmi.c x86/platform: Remove warning message for duplicate NMI handlers 2017-03-13 20:45:18 +01:00
paravirt_patch_32.c x86/paravirt: Mark unused patch_default label 2016-12-22 17:43:35 +01:00
paravirt_patch_64.c x86/paravirt: Mark unused patch_default label 2016-12-22 17:43:35 +01:00
paravirt-spinlocks.c 4.11 is going to be a relatively large release for KVM, with a little over 2017-02-22 18:22:53 -08:00
paravirt.c mm, x86: add support for PUD-sized transparent hugepages 2017-02-24 17:46:54 -08:00
pci-calgary_64.c This is a tree wide change and has been kept separate for that reason. 2017-02-25 13:45:43 -08:00
pci-dma.c This is a tree wide change and has been kept separate for that reason. 2017-02-25 13:45:43 -08:00
pci-iommu_table.c x86: Fix non-static inlines 2016-04-16 13:21:40 +02:00
pci-nommu.c treewide: Constify most dma_map_ops structures 2017-01-24 12:23:35 -05:00
pci-swiotlb.c treewide: Constify most dma_map_ops structures 2017-01-24 12:23:35 -05:00
pcspeaker.c
perf_regs.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
platform-quirks.c x86/init: Add i8042 state to the platform data 2016-12-19 11:34:15 +01:00
pmem.c x86/kernel: Audit and remove any unnecessary uses of module.h 2016-07-14 15:06:41 +02:00
probe_roms.c
process_32.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
process_64.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
process.c Second batch of KVM changes for 4.11 merge window 2017-03-04 11:36:19 -08:00
ptrace.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
pvclock.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/nmi.h> 2017-03-02 08:42:30 +01:00
quirks.c x86/quirks: Hide maybe-uninitialized warning 2016-10-25 11:45:13 +02:00
reboot_fixups_32.c
reboot.c x86/reboot/quirks: Fix typo in ASUS EeeBook X205TA reboot quirk 2017-03-10 11:58:33 +01:00
relocate_kernel_32.S
relocate_kernel_64.S
resource.c x86/e820: Prepare e280 code for switch to dynamic storage 2016-09-21 15:02:12 +02:00
rtc.c timekeeping: Ignore the bogus sleep time if pm_trace is enabled 2016-11-29 18:02:58 +01:00
setup_percpu.c x86/percpu: Remove unnecessary include of module.h, add asm/desc.h 2016-11-15 07:26:37 +01:00
setup.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-28 11:46:00 -08:00
signal_compat.c x86/signal: Remove bogus user_64bit_mode() check from sigaction_compat_abi() 2016-10-20 13:05:15 +02:00
signal.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
smp.c x86/irq, trace: Add __irq_entry annotation to x86's platform IRQ handlers 2017-01-05 08:58:49 +01:00
smpboot.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
stacktrace.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
step.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
sys_x86_64.c sched/headers: Prepare for new header dependencies before moving more code to <linux/sched/mm.h> 2017-03-02 08:42:30 +01:00
sysfb_efi.c Merge branch 'linus' into efi/core, to pick up fixes 2016-05-07 07:00:07 +02:00
sysfb_simplefb.c x86/sysfb: Fix lfb_size calculation 2016-11-16 09:38:23 +01:00
sysfb.c
tboot.c cpu/hotplug: Cleanup state names 2016-12-25 10:47:44 +01:00
tce_64.c x86/cpufeature: Remove cpu_has_clflush 2016-03-31 13:35:09 +02:00
time.c
tls.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
tls.h
topology.c
trace_clock.c
tracepoint.c tracing: Have the reg function allow to fail 2016-12-09 09:13:30 -05:00
traps.c x86/debug: Implement __WARN() using UD0 2017-03-27 10:20:28 +02:00
tsc_msr.c x86/tsc: Set TSC_KNOWN_FREQ and TSC_RELIABLE flags on Intel Atom SoCs 2016-11-18 10:58:31 +01:00
tsc_sync.c x86/tsc: Make the TSC ADJUST sanitizing work for tsc_reliable 2017-02-10 09:47:17 +01:00
tsc.c x86/tsc: Fix ART for TSC_KNOWN_FREQ 2017-03-13 19:50:23 +01:00
unwind_frame.c x86/unwind: Remove unused 'sp' parameter in unwind_dump() 2017-04-19 09:59:47 +02:00
unwind_guess.c x86/unwind: Ensure stack pointer is aligned 2017-04-18 10:30:23 +02:00
uprobes.c uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions 2016-08-12 08:29:24 +02:00
verify_cpu.S x86/cpufeature: Carve out X86_FEATURE_* 2016-01-30 11:22:17 +01:00
vm86_32.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
vmlinux.lds.S debug: Fix __bug_table[] in arch linker scripts 2017-04-03 10:22:40 +02:00
vsmp_64.c
x86_init.c x86/init: Remove i8042_detect() from platform ops 2016-12-19 11:34:15 +01:00