On Thu, Oct 16, 2008 at 12:25 PM, Dave Anderson <anderson@xxxxxxxxxx> wrote: > > ----- "Mike Snitzer" <snitzer@xxxxxxxxx> wrote: > >> I'm getting a core when I try to show slab data (kmem -[sS]) on >> 2.6.25.17 with both a live crash or saved vmcore. >> >> The core shows that the segv is coming from memset() via >> gather_cpudata_list_v2_nodes (memory.c:10119). This is with crash >> 4.0-7.4, but the same crash occurs with crash 4.0-6.3 >> (memory.c:10108) >> and older. >> >> I've also seen kmem -[sS] segfaults with older kernels too (e.g. >> 2.6.22.x). >> >> Have others experienced this? Would it be useful for me to provide >> my >> kernel config? > > No that won't help. Actually I think it may considering kmem -[sS] works perfectly fine on the same identical 2.6.22.19 kernel if various debug features are _not_ enabled, see the attached .config diff. Of note: -# CONFIG_DEBUG_SLAB is not set +CONFIG_DEBUG_SLAB=y +CONFIG_DEBUG_SLAB_LEAK=y Comparable debug features are enabled in my 2.6.25 kernel that causes crash to segfault. > It's failing in the BZERO() here: > > 10117 for (i = 0; (i < ARRAY_LENGTH(kmem_cache_s_array)) && > 10118 (cpudata[i]) && !(index); i++) { > 10119 BZERO(si->cpudata[i], sizeof(ulong) * vt->kmem_max_limit); > > What is "i" equal to when it segfaults? If you have a crash core file, > print out the contents of the global "vm_table". In that structure > there is a "kmem_max_cpus" field. If "i" is greater or equal to that, > then that's one explanation. i=0 and kmem_max_cpus=4. thanks, Mike
--- /boot/config-2.6.22.19-9.ibrix 2008-07-30 06:24:09.000000000 -0400 +++ /boot/config-2.6.22.19-9.ibrix.devel 2008-08-09 07:47:15.000000000 -0400 @@ -1,7 +1,7 @@ # # Automatically generated make config: don't edit # Linux kernel version: 2.6.22.19-9.ibrix -# Mon Jul 28 04:43:08 2008 +# Sat Aug 9 07:34:38 2008 # CONFIG_X86_64=y CONFIG_64BIT=y @@ -40,7 +40,7 @@ # # General setup # -CONFIG_LOCALVERSION="" +CONFIG_LOCALVERSION=".devel" # CONFIG_LOCALVERSION_AUTO is not set CONFIG_SWAP=y CONFIG_SYSVIPC=y @@ -2120,7 +2120,7 @@ CONFIG_EXT3_FS_SECURITY=y # CONFIG_EXT4DEV_FS is not set CONFIG_JBD=m -# CONFIG_JBD_DEBUG is not set +CONFIG_JBD_DEBUG=y CONFIG_FS_MBCACHE=y # CONFIG_REISERFS_FS is not set # CONFIG_JFS_FS is not set @@ -2334,21 +2334,22 @@ CONFIG_DETECT_SOFTLOCKUP=y CONFIG_SCHEDSTATS=y # CONFIG_TIMER_STATS is not set -# CONFIG_DEBUG_SLAB is not set +CONFIG_DEBUG_SLAB=y +CONFIG_DEBUG_SLAB_LEAK=y # CONFIG_DEBUG_RT_MUTEXES is not set # CONFIG_RT_MUTEX_TESTER is not set -# CONFIG_DEBUG_SPINLOCK is not set +CONFIG_DEBUG_SPINLOCK=y # CONFIG_DEBUG_MUTEXES is not set # CONFIG_DEBUG_LOCK_ALLOC is not set # CONFIG_PROVE_LOCKING is not set -# CONFIG_DEBUG_SPINLOCK_SLEEP is not set +CONFIG_DEBUG_SPINLOCK_SLEEP=y # CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set # CONFIG_DEBUG_KOBJECT is not set CONFIG_DEBUG_BUGVERBOSE=y CONFIG_DEBUG_INFO=y # CONFIG_DEBUG_VM is not set CONFIG_DEBUG_LIST=y -# CONFIG_FRAME_POINTER is not set +CONFIG_FRAME_POINTER=y # CONFIG_FORCED_INLINING is not set # CONFIG_RCU_TORTURE_TEST is not set # CONFIG_LKDTM is not set @@ -2356,7 +2357,7 @@ CONFIG_DEBUG_RODATA=y # CONFIG_IOMMU_DEBUG is not set CONFIG_DEBUG_STACKOVERFLOW=y -# CONFIG_DEBUG_STACK_USAGE is not set +CONFIG_DEBUG_STACK_USAGE=y # # Security options
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