x86/mce: Make timer handling more robust

Erik reported that on a preproduction hardware a CMCI storm triggers the
BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.

Reported-by: Erik Veijola <erik.veijola@intel.com>
Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/bpfc.zsh b/bpfc.zsh
index ae6eb39..04f04e7 100644
--- a/bpfc.zsh
+++ b/bpfc.zsh
@@ -12,6 +12,10 @@ typeset -A opt_args
 
 _arguments -s -S \
     "(-i --input)"{-i,--input}"[Berkeley Packet Filter file]:input:_files" \
+    "(-p --cpp)"{-p,--cpp}"[Run bpf program through C preprocessor]" \
+    "(-f --format)"{-f,--format}"[Output format]:output:(C netsniff-ng xt_bpf tcpdump)" \
+    "(-b --bypass)"{-b,--bypass}"[Bypass filter validation (e.g. for bug testing)]" \
+    "(-d --dump)"{-d,--dump}"[Dump supported instruction table]" \
     "(-V --verbose)"{-V,--verbose}"[Be more verbose]" \
     {-v,--version}"[Print version]:" \
     {-h,--help}"[Print this help]:" \