linux/arch/x86
Masami Hiramatsu b191fa96ea x86/kprobes: Avoid kretprobe recursion bug
Avoid kretprobe recursion loop bg by setting a dummy
kprobes to current_kprobe per-CPU variable.

This bug has been introduced with the asm-coded trampoline
code, since previously it used another kprobe for hooking
the function return placeholder (which only has a nop) and
trampoline handler was called from that kprobe.

This revives the old lost kprobe again.

With this fix, we don't see deadlock anymore.

And you can see that all inner-called kretprobe are skipped.

  event_1                                  235               0
  event_2                                19375           19612

The 1st column is recorded count and the 2nd is missed count.
Above shows (event_1 rec) + (event_2 rec) ~= (event_2 missed)
(some difference are here because the counter is racy)

Reported-by: Andrea Righi <righi.andrea@gmail.com>
Tested-by: Andrea Righi <righi.andrea@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: c9becf58d9 ("[PATCH] kretprobe: kretprobe-booster")
Link: http://lkml.kernel.org/r/155094064889.6137.972160690963039.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-19 14:26:07 +02:00
..
boot x86/boot: Fix incorrect ifdeffery scope 2019-03-27 14:00:51 +01:00
configs Merge branch 'akpm' (patches from Andrew) 2019-03-07 19:25:37 -08:00
crypto crypto: x86/poly1305 - Clear key material from stack in SSE2 variant 2019-02-28 14:17:59 +08:00
entry pidfd patches for v5.1-rc1 2019-03-16 13:47:14 -07:00
events perf/x86/amd: Add event map for AMD Family 17h 2019-04-18 14:31:54 +02:00
hyperv x86/hyperv: Prevent potential NULL pointer dereference 2019-03-21 12:24:39 +01:00
ia32 a.out: remove core dumping support 2019-03-05 10:00:35 -08:00
include Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-04-12 20:54:40 -07:00
kernel x86/kprobes: Avoid kretprobe recursion bug 2019-04-19 14:26:07 +02:00
kvm KVM: x86: nVMX: fix x2APIC VTPR read intercept 2019-04-05 21:08:30 +02:00
lib x86/lib: Fix indentation issue, remove extra tab 2019-03-21 12:24:38 +01:00
math-emu Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
mm x86/mm: Don't exceed the valid physical address space 2019-03-28 14:13:51 +01:00
net x32: bpf: implement jitting of JMP32 2019-01-26 13:33:02 -08:00
oprofile
pci x86/PCI: Fixup RTIT_BAR of Intel Denverton Trace Hub 2019-02-07 08:43:58 -06:00
platform x86/realmode: Make set_real_mode_mem() static inline 2019-03-29 10:16:27 +01:00
power mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
purgatory
ras
realmode x86/realmode: Make set_real_mode_mem() static inline 2019-03-29 10:16:27 +01:00
tools x86: Clean up 'sizeof x' => 'sizeof(x)' 2018-10-29 07:13:28 +01:00
um Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-05 14:08:26 -08:00
video
xen Merge branch 'akpm' (patches from Andrew) 2019-03-12 10:39:53 -07:00
.gitignore
Kbuild KVM: x86: Allow Qemu/KVM to use PVH entry point 2018-12-13 13:41:49 -05:00
Kconfig x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y 2019-03-28 13:34:58 +01:00
Kconfig.cpu
Kconfig.debug efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation 2019-02-04 08:27:30 +01:00
Makefile x86/retpolines: Disable switch jump tables when retpolines are enabled 2019-03-28 13:39:48 +01:00
Makefile_32.cpu
Makefile.um x86, powerpc: Remove -funit-at-a-time compiler option entirely 2018-12-09 11:55:32 +01:00