Lines Matching +full:proc +full:- +full:id
1 .. SPDX-License-Identifier: GPL-2.0
4 The /proc Filesystem
8 /proc/sys Terrehon Bowden <[email protected]>, October 7 1999
11 move /proc/sys Shen Feng <[email protected]> April 1 2009
24 1.1 Process-Specific Subdirectories
26 1.3 IDE devices in /proc/ide
27 1.4 Networking info in /proc/net
29 1.6 Parallel port info in /proc/parport
30 1.7 TTY info in /proc/tty
31 1.8 Miscellaneous kernel statistics in /proc/stat
36 3 Per-Process Parameters
37 3.1 /proc/<pid>/oom_adj & /proc/<pid>/oom_score_adj - Adjust the oom-killer
39 3.2 /proc/<pid>/oom_score - Display current oom-killer score
40 3.3 /proc/<pid>/io - Display the IO accounting fields
41 3.4 /proc/<pid>/coredump_filter - Core dump filtering settings
42 3.5 /proc/<pid>/mountinfo - Information about mounts
43 3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm
44 3.7 /proc/<pid>/task/<tid>/children - Information about task children
45 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file
46 3.9 /proc/<pid>/map_files - Information about memory mapped files
47 3.10 /proc/<pid>/timerslack_ns - Task timerslack value
48 3.11 /proc/<pid>/patch_state - Livepatch patch operation state
49 3.12 /proc/<pid>/arch_status - Task architecture specific information
50 3.13 /proc/<pid>/fd - List of symlinks to open files
51 3.14 /proc/<pid/ksm_stat - Information about the process's ksm status.
62 ------------------------
66 /proc file system and we've used many freely available sources to write these
70 we know, it is the first 'all-in-one' document about the /proc file system. It
73 It also only covers IPv4 networking, not IPv6 nor other protocols - sorry. But
89 https://www.kernel.org/doc/html/latest/filesystems/proc.html
92 mailing list at linux-[email protected] and/or try to reach me at
96 ---------------
106 ---------------
107 * Investigating the properties of the pseudo file system /proc and its
109 * Examining /proc's structure
113 ------------------------------------------------------------------------------
115 The proc file system acts as an interface to internal data structures in the
119 First, we'll take a look at the read-only parts of /proc. In Chapter 2, we
120 show you how you can use /proc/sys to change settings.
122 1.1 Process-Specific Subdirectories
123 -----------------------------------
125 The directory /proc contains (among other things) one subdirectory for each
126 process running on the system, which is named after the process ID (PID).
129 subdirectory has the entries listed in Table 1-1.
131 Note that an open file descriptor to /proc/<pid> or to any of its
134 open /proc/<pid> file descriptors corresponding to dead processes
136 also assigned the process ID <pid>. Instead, operations on these FDs
139 .. table:: Table 1-1: Process specific entries in /proc
158 symbol the task is blocked in - or "0" if not blocked.
170 read the file /proc/PID/status::
172 >cat /proc/self/status
221 the ps command. In fact, ps uses the proc file system to obtain its
223 file /proc/PID/status. It fields are described in table 1-2.
226 memory usage. Its seven fields are explained in Table 1-3. The stat file
228 explained in Table 1-4.
234 snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table.
237 .. table:: Table 1-2: Contents of the status fields (as of 4.19)
247 Tgid thread group ID
248 Ngid NUMA group ID (0 if none)
249 Pid process id
250 PPid process id of the parent process
257 NStgid descendant namespace thread group ID hierarchy
258 NSpid descendant namespace process ID hierarchy
259 NSpgid descendant namespace process group ID hierarchy
260 NSsid descendant namespace session ID hierarchy
311 .. table:: Table 1-3: Contents of the statm fields (as of 2.6.8-rc3)
329 .. table:: Table 1-4: Contents of the stat fields (as of 2.6.30-rc7)
334 pid process id
338 ppid process id of the parent process
340 sid session id
370 use /proc/PID/wchan instead)
391 The /proc/PID/maps file contains the currently mapped memory regions and
398 08048000-08049000 r-xp 00000000 03:00 8312 /opt/test
399 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test
400 0804a000-0806b000 rw-p 00000000 00:00 0 [heap]
401 a7cb1000-a7cb2000 ---p 00000000 00:00 0
402 a7cb2000-a7eb2000 rw-p 00000000 00:00 0
403 a7eb2000-a7eb3000 ---p 00000000 00:00 0
404 a7eb3000-a7ed5000 rw-p 00000000 00:00 0
405 a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6
406 a8008000-a800a000 r--p 00133000 03:00 4222 /lib/libc.so.6
407 a800a000-a800b000 rw-p 00135000 03:00 4222 /lib/libc.so.6
408 a800b000-a800e000 rw-p 00000000 00:00 0
409 a800e000-a8022000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0
410 a8022000-a8023000 r--p 00013000 03:00 14462 /lib/libpthread.so.0
411 a8023000-a8024000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0
412 a8024000-a8027000 rw-p 00000000 00:00 0
413 a8027000-a8043000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2
414 a8043000-a8044000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2
415 a8044000-a8045000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2
416 aff35000-aff4a000 rw-p 00000000 00:00 0 [stack]
417 ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso]
447 Starting with 6.11 kernel, /proc/PID/maps provides an alternative
448 ioctl()-based API that gives ability to flexibly and efficiently query and
456 The /proc/PID/smaps is an extension based on maps, showing the memory
460 08048000-080bc000 r-xp 00000000 03:02 13130 /bin/bash
489 the mapping in /proc/PID/maps. Following lines show the size of the
516 "KSM" reports how many of the pages are KSM pages. Note that KSM-placed zeropages
534 "Swap" shows how much would-be-anonymous memory is also used, but out on swap.
537 replaced by copy-on-write) part of the underlying shmem object out on swap.
583 uw userfaultfd wr-protect tracking
590 be vanished or the reverse -- new added. Interpretation of their meaning
597 Note: reading /proc/PID/maps or /proc/PID/smaps is inherently racy (consistent
609 The /proc/PID/smaps_rollup file includes the same fields as /proc/PID/smaps,
613 - Pss_Anon
614 - Pss_File
615 - Pss_Shmem
623 The /proc/PID/clear_refs is used to reset the PG_Referenced and ACCESSED/YOUNG
625 soft-dirty bit on pte (see Documentation/admin-guide/mm/soft-dirty.rst
629 > echo 1 > /proc/PID/clear_refs
633 > echo 2 > /proc/PID/clear_refs
637 > echo 3 > /proc/PID/clear_refs
639 To clear the soft-dirty bit::
641 > echo 4 > /proc/PID/clear_refs
646 > echo 5 > /proc/PID/clear_refs
648 Any other value written to /proc/PID/clear_refs will have no effect.
650 The /proc/pid/pagemap gives the PFN, which can be used to find the pageflags
651 using /proc/kpageflags and number of times a page is mapped using
652 /proc/kpagecount. For detailed explanation, see
653 Documentation/admin-guide/mm/pagemap.rst.
655 The /proc/pid/numa_maps is an extension based on maps, showing the memory
664 3206000000 default file=/lib64/ld-2.12.so mapped=26 mapmax=6 N0=24 N3=2 kernelpagesize_kB=4
665 320621f000 default file=/lib64/ld-2.12.so anon=1 dirty=1 N3=1 kernelpagesize_kB=4
666 3206220000 default file=/lib64/ld-2.12.so anon=1 dirty=1 N3=1 kernelpagesize_kB=4
668 …3206800000 default file=/lib64/libc-2.12.so mapped=59 mapmax=21 active=55 N0=41 N3=18 kernelpagesi…
669 320698b000 default file=/lib64/libc-2.12.so
670 3206b8a000 default file=/lib64/libc-2.12.so anon=2 dirty=2 N3=2 kernelpagesize_kB=4
671 3206b8e000 default file=/lib64/libc-2.12.so anon=1 dirty=1 N3=1 kernelpagesize_kB=4
683 "policy" reports the NUMA memory policy set for the mapping (see Documentation/admin-guide/mm/numa_…
690 ---------------
694 /proc and are listed in Table 1-5. Not all of these will be present in your
698 .. table:: Table 1-5: Kernel info in /proc
747 pci Deprecated info of PCI bus (new way -> /proc/bus/pci/,
765 they are used for by looking in the file /proc/interrupts::
767 > cat /proc/interrupts
769 0: 8728810 XT-PIC timer
770 1: 895 XT-PIC keyboard
771 2: 0 XT-PIC cascade
772 3: 531695 XT-PIC aha152x
773 4: 2014133 XT-PIC serial
774 5: 44401 XT-PIC pcnet_cs
775 8: 2 XT-PIC rtc
776 11: 8 XT-PIC i82365
777 12: 182918 XT-PIC PS/2 Mouse
778 13: 1 XT-PIC fpu
779 14: 1232265 XT-PIC ide0
780 15: 7 XT-PIC ide1
786 > cat /proc/interrupts
789 0: 1243498 1214548 IO-APIC-edge timer
790 1: 8949 8958 IO-APIC-edge keyboard
791 2: 0 0 XT-PIC cascade
792 5: 11286 10161 IO-APIC-edge soundblaster
793 8: 1 0 IO-APIC-edge rtc
794 9: 27422 27407 IO-APIC-edge 3c503
795 12: 113645 113873 IO-APIC-edge PS/2 Mouse
796 13: 0 0 XT-PIC fpu
797 14: 22491 24012 IO-APIC-edge ide0
798 15: 2183 2415 IO-APIC-edge ide1
799 17: 30564 30414 IO-APIC-level eth0
800 18: 177 164 IO-APIC-level bttv
810 ERR is incremented in the case of errors in the IO-APIC bus (the bus that
812 the IO-APIC automatically retry the transmission, so it should not be a big
813 problem, but you should read the SMP-FAQ.
815 In 2.6.2* /proc/interrupts was expanded again. This time the goal was for
816 /proc/interrupts to display every IRQ vector in use by the system, not
847 Of some interest is the introduction of the /proc/irq directory to 2.4.
855 > ls /proc/irq/
858 > ls /proc/irq/0/
864 > echo 1 > /proc/irq/10/smp_affinity
871 > cat /proc/irq/0/smp_affinity
877 > cat /proc/irq/0/smp_affinity_list
878 1024-1031
880 The default_smp_affinity mask applies to all non-active IRQs, which are the
882 /proc/irq/[0-9]* directory.
891 The way IRQs are routed is handled by the IO-APIC, and it's Round Robin
894 best choice for almost everyone. [Note this applies only to those IO-APIC's
897 There are three more important subdirectories in /proc: net, scsi, and sys.
910 > cat /proc/buddyinfo
929 > cat /proc/pagetypeinfo
952 X86-64. By keeping pages grouped based on their ability to move, the kernel
953 can reclaim pages within a page block to satisfy a high-order allocation.
957 by migrate-type and finishes with details on how many page blocks of each
983 > tail -n +3 /proc/allocinfo | sort -rn
988 13377536 234 block/blk-mq.c:3421 func:blk_mq_alloc_rqs
1007 /proc/net/sockstat for TCP memory allocations.
1013 > cat /proc/meminfo
1091 In-memory cache for files read from the disk (the
1135 Non-file backed pages mapped into userspace page tables
1145 in-kernel data structures cache
1173 CommitLimit = ([total RAM pages] - [total huge TLB pages]) *
1181 in mm/overcommit-accounting.
1216 Non-file backed huge pages mapped into userspace page tables
1232 See Documentation/admin-guide/mm/hugetlbpage.rst.
1259 > cat /proc/vmallocinfo
1260 0xffffc20000000000-0xffffc20000201000 2101248 alloc_large_system_hash+0x204 ...
1262 0xffffc20000201000-0xffffc20000302000 1052672 alloc_large_system_hash+0x204 ...
1264 0xffffc20000302000-0xffffc20000304000 8192 acpi_tb_verify_table+0x21/0x4f...
1266 0xffffc20000304000-0xffffc20000307000 12288 acpi_tb_verify_table+0x21/0x4f...
1268 0xffffc2000031d000-0xffffc2000031f000 8192 init_vdso_vars+0x112/0x210
1269 0xffffc2000031f000-0xffffc2000032b000 49152 cramfs_uncompress_init+0x2e ...
1271 0xffffc2000033a000-0xffffc2000033d000 12288 sys_swapon+0x640/0xac0 ...
1273 0xffffc20000347000-0xffffc2000034c000 20480 xt_alloc_table_info+0xfe ...
1275 0xffffffffa0000000-0xffffffffa000f000 61440 sys_init_module+0xc27/0x1d00 ...
1277 0xffffffffa000f000-0xffffffffa0014000 20480 sys_init_module+0xc27/0x1d00 ...
1279 0xffffffffa0014000-0xffffffffa0017000 12288 sys_init_module+0xc27/0x1d00 ...
1281 0xffffffffa0017000-0xffffffffa0022000 45056 sys_init_module+0xc27/0x1d00 ...
1292 > cat /proc/softirqs
1304 1.3 Networking info in /proc/net
1305 --------------------------------
1307 The subdirectory /proc/net follows the usual pattern. Table 1-8 shows the
1309 support this. Table 1-9 lists the files and their meaning.
1312 .. table:: Table 1-8: IPv6 info in /proc/net
1328 .. table:: Table 1-9: Network info in /proc/net
1350 softnet_stat Per-CPU incoming packets queues statistics of online CPUs
1365 > cat /proc/net/dev
1366 Inter-|Receive |[...
1379 example, the bond0 device will have a directory called /proc/net/bond0/.
1385 -------------
1388 subdirectory named after the driver for this adapter in /proc/scsi.
1389 You'll also see a list of all recognized SCSI devices in /proc/scsi::
1391 >cat /proc/scsi/scsi
1393 Host: scsi0 Channel: 00 Id: 00 Lun: 00
1395 Type: Direct-Access ANSI SCSI revision: 03
1396 Host: scsi0 Channel: 00 Id: 06 Lun: 00
1397 Vendor: PIONEER Model: CD-ROM DR-U06S Rev: 1.04
1398 Type: CD-ROM ANSI SCSI revision: 02
1405 AHA-2940 SCSI adapter::
1407 > cat /proc/scsi/aic7xxx/0
1415 SCSI Adapter: Adaptec AHA-294X Ultra SCSI host adapter
1447 1.5 Parallel port info in /proc/parport
1448 ---------------------------------------
1450 The directory /proc/parport contains information about the parallel ports of
1454 These directories contain the four files shown in Table 1-10.
1457 .. table:: Table 1-10: Files in /proc/parport
1462 autoprobe Any IEEE-1284 device ID information that has been acquired.
1472 1.6 TTY info in /proc/tty
1473 -------------------------
1476 directory /proc/tty. You'll find entries for drivers and line disciplines in
1477 this directory, as shown in Table 1-11.
1480 .. table:: Table 1-11: Files in /proc/tty
1491 /proc/tty/drivers::
1493 > cat /proc/tty/drivers
1494 pty_slave /dev/pts 136 0-255 pty:slave
1495 pty_master /dev/ptm 128 0-255 pty:master
1496 pty_slave /dev/ttyp 3 0-255 pty:slave
1497 pty_master /dev/pty 2 0-255 pty:master
1498 serial /dev/cua 5 64-67 serial:callout
1499 serial /dev/ttyS 4 64-67 serial
1504 unknown /dev/tty 4 1-63 console
1507 1.7 Miscellaneous kernel statistics in /proc/stat
1508 -------------------------------------------------
1511 /proc/stat file. All of the numbers reported in this file are aggregates
1514 > cat /proc/stat
1533 - user: normal processes executing in user mode
1534 - nice: niced processes executing in user mode
1535 - system: processes executing in kernel mode
1536 - idle: twiddling thumbs
1537 - iowait: In a word, iowait stands for waiting for I/O to complete. But there
1543 2. In a multi-core CPU, the task waiting for I/O to complete is not running
1545 3. The value of iowait field in /proc/stat will decrease in certain
1548 So, the iowait is not reliable by reading from /proc/stat.
1549 - irq: servicing interrupts
1550 - softirq: servicing softirqs
1551 - steal: involuntary wait
1552 - guest: running a normal guest
1553 - guest_nice: running a niced guest
1583 -------------------------------
1586 /proc/fs/ext4. Each mounted filesystem will have a directory in
1587 /proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or
1588 /proc/fs/ext4/sda9 or /proc/fs/ext4/dm-0). The files in each per-device
1589 directory are shown in Table 1-12, below.
1591 .. table:: Table 1-12: Files in /proc/fs/ext4/<devname>
1598 1.9 /proc/consoles
1599 -------------------
1603 /dev/console, you may simply look into the file /proc/consoles::
1605 > cat /proc/consoles
1606 tty0 -WU (ECp) 4:7
1607 ttyS0 -W- (Ep) 4:64
1611 +--------------------+-------------------------------------------------------+
1617 +--------------------+-------------------------------------------------------+
1624 +--------------------+-------------------------------------------------------+
1627 +--------------------+-------------------------------------------------------+
1630 -------
1632 The /proc file system serves information about the running system. It not only
1636 The directory structure of /proc reflects the types of information and makes
1643 ---------------
1645 * Modifying kernel parameters by writing into files found in /proc/sys
1647 * Review of the /proc/sys file tree
1649 ------------------------------------------------------------------------------
1651 A very interesting part of /proc is the directory /proc/sys. This is not only
1663 The files in /proc/sys can be used to fine tune and monitor miscellaneous and
1667 very careful when writing to any of these files. The entries in /proc may
1673 Please see: Documentation/admin-guide/sysctl/ directory for descriptions of
1677 -------
1681 /proc/sys tree can not only be read, but also modified. You can use the echo
1686 Chapter 3: Per-process Parameters
1689 3.1 /proc/<pid>/oom_adj & /proc/<pid>/oom_score_adj- Adjust the oom-killer score
1690 --------------------------------------------------------------------------------
1711 The value of /proc/<pid>/oom_score_adj is added to the badness score before it
1712 is used to determine which task to kill. Acceptable values range from -1000
1715 task or completely disabling it. The lowest possible value, -1000, is
1720 consider for each task. Setting a /proc/<pid>/oom_score_adj value of +500, for
1723 50% more memory. A value of -500, on the other hand, would be roughly
1727 For backwards compatibility with previous kernels, /proc/<pid>/oom_adj may also
1728 be used to tune the badness score. Its acceptable values range from -16
1729 (OOM_ADJUST_MIN) to +15 (OOM_ADJUST_MAX) and a special value of -17
1731 scaled linearly with /proc/<pid>/oom_score_adj.
1733 The value of /proc/<pid>/oom_score_adj may be reduced no lower than the last
1738 3.2 /proc/<pid>/oom_score - Display current oom-killer score
1739 -------------------------------------------------------------
1741 This file can be used to check the current score used by the oom-killer for
1742 any given <pid>. Use it together with /proc/<pid>/oom_score_adj to tune which
1743 process should be killed in an out-of-memory situation.
1749 3.3 /proc/<pid>/io - Display the IO accounting fields
1750 -------------------------------------------------------
1762 test:/tmp # cat /proc/3828/io
1816 accurate for block-backed filesystems. <please add status regarding NFS and
1825 the storage layer. This is done at page-dirtying time.
1844 At its current implementation state, this is a bit racy on 32-bit machines:
1845 if process A reads process B's /proc/pid/io while process B is updating one
1846 of those 64-bit counters, process A could see an intermediate result.
1852 3.4 /proc/<pid>/coredump_filter - Core dump filtering settings
1853 ---------------------------------------------------------------
1857 Conversely, sometimes we want to save file-backed memory segments into a core
1860 /proc/<pid>/coredump_filter allows you to customize which memory segments
1867 - (bit 0) anonymous private memory
1868 - (bit 1) anonymous shared memory
1869 - (bit 2) file-backed private memory
1870 - (bit 3) file-backed shared memory
1871 - (bit 4) ELF header pages in file-backed private memory areas (it is
1873 - (bit 5) hugetlb private memory
1874 - (bit 6) hugetlb shared memory
1875 - (bit 7) DAX private memory
1876 - (bit 8) DAX shared memory
1881 Note that bits 0-4 don't affect hugetlb or DAX memory. hugetlb memory is
1882 only affected by bit 5-6, and DAX is only affected by bits 7-8.
1888 write 0x31 to the process's proc file::
1890 $ echo 0x31 > /proc/1234/coredump_filter
1896 $ echo 0x7 > /proc/self/coredump_filter
1899 3.5 /proc/<pid>/mountinfo - Information about mounts
1900 --------------------------------------------------------
1904 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
1907 (1) mount ID: unique identifier of the mount (may be reused after umount)
1908 (2) parent ID: ID of parent (or of self for the top of the mount tree)
1939 3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm
1940 --------------------------------------------------------
1948 3.7 /proc/<pid>/task/<tid>/children - Information about task children
1949 -------------------------------------------------------------------------
1954 Note the "first level" here -- if a child has its own children they will
1955 not be listed here; one needs to read /proc/<children-pid>/task/<tid>/children
1965 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file
1966 ---------------------------------------------------------------
1968 files have at least four fields -- 'pos', 'flags', 'mnt_id' and 'ino'.
1972 mount ID of the file system containing the opened file [see 3.5
1973 /proc/<pid>/mountinfo for details]. 'ino' represents the inode number of
1999 eventfd-count: 5a
2001 where 'eventfd-count' is hex value of a counter.
2044 …inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_han…
2053 fields 'fhandle-bytes', 'fhandle-type' and 'f_handle', all in hex
2067 fanotify flags:10 event-flags:0
2069 …fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type…
2071 where fanotify 'flags' and 'event-flags' are values used in fanotify_init
2117 exp_name: system-heap
2122 3.9 /proc/<pid>/map_files - Information about memory mapped files
2123 ---------------------------------------------------------------------
2127 | lr-------- 1 root root 64 Jan 27 11:24 333c600000-333c620000 -> /usr/lib64/ld-2.18.so
2128 | lr-------- 1 root root 64 Jan 27 11:24 333c81f000-333c820000 -> /usr/lib64/ld-2.18.so
2129 | lr-------- 1 root root 64 Jan 27 11:24 333c820000-333c821000 -> /usr/lib64/ld-2.18.so
2131 | lr-------- 1 root root 64 Jan 27 11:24 35d0421000-35d0422000 -> /usr/lib64/libselinux.so.1
2132 | lr-------- 1 root root 64 Jan 27 11:24 400000-41a000 -> /usr/bin/ls
2135 vm_area_struct::vm_start-vm_area_struct::vm_end.
2138 files in a fast way instead of parsing /proc/<pid>/maps or
2139 /proc/<pid>/smaps, both of which contain many more records. At the same
2144 3.10 /proc/<pid>/timerslack_ns - Task timerslack value
2145 ---------------------------------------------------------
2155 Valid values are from 0 - ULLONG_MAX
2160 3.11 /proc/<pid>/patch_state - Livepatch patch operation state
2161 -----------------------------------------------------------------
2165 A value of '-1' indicates that no patch is in transition.
2177 3.12 /proc/<pid>/arch_status - task architecture specific status
2178 -------------------------------------------------------------------
2187 $ cat /proc/6753/arch_status
2218 A special value of '-1' indicates that no AVX512 usage was recorded, thus
2222 3.13 /proc/<pid>/fd - List of symlinks to open files
2223 -------------------------------------------------------
2227 lr-x------ 1 root root 64 Sep 20 17:53 0 -> /dev/null
2228 l-wx------ 1 root root 64 Sep 20 17:53 1 -> /dev/null
2229 lrwx------ 1 root root 64 Sep 20 17:53 10 -> 'socket:[12539]'
2230 lrwx------ 1 root root 64 Sep 20 17:53 11 -> 'socket:[12540]'
2231 lrwx------ 1 root root 64 Sep 20 17:53 12 -> 'socket:[12542]'
2234 of stat() output for /proc/<pid>/fd for fast access.
2235 -------------------------------------------------------
2237 3.14 /proc/<pid/ksm_stat - Information about the process's ksm status
2238 ---------------------------------------------------------------------
2247 / # cat /proc/self/ksm_stat
2263 addresses. KSM will generate a ksm_rmap_item for each ksm-scanned page of
2277 /proc/<pid>/ksm_merging_pages shows.
2303 Documentation/admin-guide/mm/ksm.rst.
2310 ---------------------
2315 hidepid= Set /proc/<pid>/ access mode.
2320 hidepid=off or hidepid=0 means classic mode - everybody may access all
2321 /proc/<pid>/ directories (default).
2323 hidepid=noaccess or hidepid=1 means users may not access any /proc/<pid>/
2327 behaviour). As an additional bonus, as /proc/<pid>/cmdline is unaccessible for
2331 hidepid=invisible or hidepid=2 means hidepid=1 plus all /proc/<pid>/ will be
2334 by "kill -0 $PID"), but it hides process's uid and gid, which may be learned by
2335 stat()'ing /proc/<pid>/ otherwise. It greatly complicates an intruder's task of
2341 /proc/<pid>/ directories that the caller can ptrace.
2360 # grep ^proc /proc/mounts
2361 proc /proc proc rw,relatime,hidepid=2 0 0
2363 # strace -e mount mount -o hidepid=1 -t proc proc /tmp/proc
2364 mount("proc", "/tmp/proc", "proc", 0, "hidepid=1") = 0
2367 # grep ^proc /proc/mounts
2368 proc /proc proc rw,relatime,hidepid=2 0 0
2369 proc /tmp/proc proc rw,relatime,hidepid=2 0 0
2374 # mount -o remount,hidepid=1 -t proc proc /tmp/proc
2376 # grep ^proc /proc/mounts
2377 proc /proc proc rw,relatime,hidepid=1 0 0
2378 proc /tmp/proc proc rw,relatime,hidepid=1 0 0
2387 # mount -o hidepid=invisible -t proc proc /proc
2388 # mount -o hidepid=noaccess -t proc proc /tmp/proc
2389 # grep ^proc /proc/mounts
2390 proc /proc proc rw,relatime,hidepid=invisible 0 0
2391 proc /tmp/proc proc rw,relatime,hidepid=noaccess 0 0