February 13, 2017

CONFIG_DEBUG_KMEMLEAK does not create /sys/kernel/debug/kmemleak

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As seen below, a newly compiled 4.4.48 kernel, with CONFIG_DEBUG_KMEMLEAK enabled, is not creating the kmemleak file in /sys/kernel/debug. (Note that kmemleak is not being explicitly disabled via the kernel command line options either; I've also tried adding 'kmemleak=on' to the kernel command-line just in case, but this didn't help...)

[root@myVMslot12 ~]# uname -a
Linux myVMslot12 4.4.48 #2 SMP Fri Feb 10 11:24:11 EST 2017 x86_64 x86_64 x86_64 GNU/Linux

[root@myVMslot12 ~]# ls /sys/kernel/debug/kmemleak
ls: cannot access /sys/kernel/debug/kmemleak: No such file or directory

[root@myVMslot12 ~]# ls /sys/kernel/debug/
acpi cleancache extfrag ixgbe pm_qos sched_features suspend_stats virtio-ports
bdi dma_buf fault_around_bytes kprobes ras sleep_time tracing wakeup_sources
boot_params dynamic_debug hid mce regmap sunrpc usb x86

[root@myVMslot12 ~]# cat /proc/config.gz | gzip -d -c | grep KMEMLEAK
CONFIG_HAVE_DEBUG_KMEMLEAK=y
CONFIG_DEBUG_KMEMLEAK=y
CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=400
# CONFIG_DEBUG_KMEMLEAK_TEST is not set
# CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF is not set

[root@myVMslot12 ~]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-4.4.48 root=UUID=b419f9ff-80ce-459e-855c-614d86a48105 ro rd.md=0 rd.lvm=0 rd.dm=0 KEYTABLE=us quiet SYSFONT=latarcyrheb-sun16 rhgb crashkernel=auto console=ttyS0,115200n8 rd.luks=0 LANG=en_US.UTF-8 audit=1 libata.force=noncq erst_disable</pre>

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