forked from Minki/linux
b2f5de0334
* Test lookup in /proc/self/fd. "map_files" lookup story showed that lookup is not that simple. * Test that all those symlinks open the same file. Check with (st_dev, st_info). * Test that kernel threads do not have anything in their /proc/*/fd/ directory. Now this is where things get interesting. First, kernel threads aren't pinned by /proc/self or equivalent, thus some "atomicity" is required. Second, ->comm can contain whitespace and ')'. No, they are not escaped. Third, the only reliable way to check if process is kernel thread appears to be field #9 in /proc/*/stat. This field is struct task_struct::flags in decimal! Check is done by testing PF_KTHREAD flags like we do in kernel. PF_KTREAD value is a part of userspace ABI !!! Other methods for determining kernel threadness are not reliable: * RSS can be 0 if everything is swapped, even while reading from /proc/self. * ->total_vm CAN BE ZERO if process is finishing munmap(NULL, whole address space); * /proc/*/maps and similar files can be empty because unmapping everything works. Read returning 0 can't distinguish between kernel thread and such suicide process. Link: http://lkml.kernel.org/r/20180505000414.GA15090@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| accounting | ||
| arch | ||
| bpf | ||
| build | ||
| cgroup | ||
| firewire | ||
| gpio | ||
| hv | ||
| iio | ||
| include | ||
| kvm/kvm_stat | ||
| laptop | ||
| leds | ||
| lib | ||
| memory-model | ||
| nfsd | ||
| objtool | ||
| pci | ||
| pcmcia | ||
| perf | ||
| power | ||
| scripts | ||
| spi | ||
| testing | ||
| thermal/tmon | ||
| time | ||
| usb | ||
| virtio | ||
| vm | ||
| wmi | ||
| Makefile | ||