# git rev-parse -q --verify 093b995e3b55a0ae0670226ddfcb05bfbf0099ae^{commit}
093b995e3b55a0ae0670226ddfcb05bfbf0099ae
already have revision, skipping fetch
# git checkout -q -f -B kisskb 093b995e3b55a0ae0670226ddfcb05bfbf0099ae
# git clean -qxdf
# git log -1
commit 093b995e3b55a0ae0670226ddfcb05bfbf0099ae
Author: Huang Ying <ying.huang@intel.com>
Date:   Mon Mar 20 14:26:42 2017 +0800

    mm, swap: Remove WARN_ON_ONCE() in free_swap_slot()
    
    Before commit 452b94b8c8c7 ("mm/swap: don't BUG_ON() due to
    uninitialized swap slot cache"), the following bug is reported,
    
      ------------[ cut here ]------------
      kernel BUG at mm/swap_slots.c:270!
      invalid opcode: 0000 [#1] SMP
      CPU: 5 PID: 1745 Comm: (sd-pam) Not tainted 4.11.0-rc1-00243-g24c534bb161b #1
      Hardware name: System manufacturer System Product Name/Z170-K, BIOS 1803 05/06/2016
      RIP: 0010:free_swap_slot+0xba/0xd0
      Call Trace:
       swap_free+0x36/0x40
       do_swap_page+0x360/0x6d0
       __handle_mm_fault+0x880/0x1080
       handle_mm_fault+0xd0/0x240
       __do_page_fault+0x232/0x4d0
       do_page_fault+0x20/0x70
       page_fault+0x22/0x30
      ---[ end trace aefc9ede53e0ab21 ]---
    
    This is raised by the BUG_ON(!swap_slot_cache_initialized) in
    free_swap_slot().  This is incorrect, because even if the swap slots
    cache fails to be initialized, the swap should operate properly without
    the swap slots cache.  And the use_swap_slot_cache check later in the
    function will protect the uninitialized swap slots cache case.
    
    In commit 452b94b8c8c7, the BUG_ON() is replaced by WARN_ON_ONCE().  In
    the patch, the WARN_ON_ONCE() is removed too.
    
    Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
    Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
    Cc: Michal Hocko <mhocko@suse.com>
    Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-gcc --version
# < git log --format=%s --max-count=1 093b995e3b55a0ae0670226ddfcb05bfbf0099ae
# < make -j 48 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-  randconfig
KCONFIG_SEED=0xF779D644
warning: (X86_INTEL_LPSS && INTEL_SOC_DTS_IOSF_CORE && SND_SST_IPC_ACPI && MMC_SDHCI_ACPI && PUNIT_ATOM_DEBUG) selects IOSF_MBI which has unmet direct dependencies (PCI)
# Added to kconfig CONFIG_STANDALONE=y
# Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y
# yes \n | make -j 48 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-  oldconfig
yes: standard output: Broken pipe
yes: write error
# make -j 48 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-  
make[1]: Entering directory '/home/kisskb/slave/build/linus_i386-randconfig_i386'
  GEN     ./Makefile
scripts/kconfig/conf  --silentoldconfig Kconfig
warning: (X86_INTEL_LPSS && INTEL_SOC_DTS_IOSF_CORE && SND_SST_IPC_ACPI && MMC_SDHCI_ACPI && PUNIT_ATOM_DEBUG) selects IOSF_MBI which has unmet direct dependencies (PCI)
warning: (X86_INTEL_LPSS && INTEL_SOC_DTS_IOSF_CORE && SND_SST_IPC_ACPI && MMC_SDHCI_ACPI && PUNIT_ATOM_DEBUG) selects IOSF_MBI which has unmet direct dependencies (PCI)
  SYSTBL  arch/x86/entry/syscalls/../../include/generated/asm/syscalls_32.h
  HYPERCALLS arch/x86/entry/syscalls/../../include/generated/asm/xen-hypercalls.h
  SYSHDR  arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_32.h
  SYSHDR  arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_64.h
  SYSHDR  arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_x32.h
  CHK     include/config/kernel.release
Cannot use CONFIG_CC_STACKPROTECTOR_REGULAR: -fstack-protector available but compiler is broken
/home/kisskb/slave/src/Makefile:1075: recipe for target 'prepare-compiler-check' failed
make[1]: *** [prepare-compiler-check] Error 1
make[1]: *** Waiting for unfinished jobs....
  UPD     include/config/kernel.release
make[1]: *** wait: No child processes.  Stop.
Makefile:152: recipe for target 'sub-make' failed
make: *** [sub-make] Error 2
Command 'make -j 48 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-  ' returned non-zero exit status 2
# rm -rf /home/kisskb/slave/build/linus_i386-randconfig_i386
# Build took: 0:00:04.917668