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NAME | DESCRIPTION | SEE ALSO | COLOPHON |
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proc_pid_maps(5) File Formats Manual proc_pid_maps(5)
/proc/pid/maps - mapped memory regions
/proc/pid/maps
A file containing the currently mapped memory regions and
their access permissions. See mmap(2) for some further
information about memory mappings.
Permission to access this file is governed by a ptrace
access mode PTRACE_MODE_READ_FSCREDS check; see ptrace(2).
The format of the file is:
address perms offset dev inode pathname
00400000-00452000 r-xp 00000000 08:02 173521 /usr/bin/dbus-daemon
00651000-00652000 r--p 00051000 08:02 173521 /usr/bin/dbus-daemon
00652000-00655000 rw-p 00052000 08:02 173521 /usr/bin/dbus-daemon
00e03000-00e24000 rw-p 00000000 00:00 0 [heap]
00e24000-011f7000 rw-p 00000000 00:00 0 [heap]
...
35b1800000-35b1820000 r-xp 00000000 08:02 135522 /usr/lib64/ld-2.15.so
35b1a1f000-35b1a20000 r--p 0001f000 08:02 135522 /usr/lib64/ld-2.15.so
35b1a20000-35b1a21000 rw-p 00020000 08:02 135522 /usr/lib64/ld-2.15.so
35b1a21000-35b1a22000 rw-p 00000000 00:00 0
35b1c00000-35b1dac000 r-xp 00000000 08:02 135870 /usr/lib64/libc-2.15.so
35b1dac000-35b1fac000 ---p 001ac000 08:02 135870 /usr/lib64/libc-2.15.so
35b1fac000-35b1fb0000 r--p 001ac000 08:02 135870 /usr/lib64/libc-2.15.so
35b1fb0000-35b1fb2000 rw-p 001b0000 08:02 135870 /usr/lib64/libc-2.15.so
...
f2c6ff8c000-7f2c7078c000 rw-p 00000000 00:00 0 [stack:986]
...
7fffb2c0d000-7fffb2c2e000 rw-p 00000000 00:00 0 [stack]
7fffb2d48000-7fffb2d49000 r-xp 00000000 00:00 0 [vdso]
The address field is the address space in the process that
the mapping occupies. The perms field is a set of
permissions:
r = read
w = write
x = execute
s = shared
p = private (copy on write)
The offset field is the offset into the file/whatever; dev
is the device (major:minor); inode is the inode on that
device. 0 indicates that no inode is associated with the
memory region, as would be the case with BSS
(uninitialized data).
The pathname field will usually be the file that is
backing the mapping. For ELF files, you can easily
coordinate with the offset field by looking at the Offset
field in the ELF program headers (readelf -l).
There are additional helpful pseudo-paths:
[stack]
The initial process's (also known as the main
thread's) stack.
[stack:tid] (from Linux 3.4 to Linux 4.4)
A thread's stack (where the tid is a thread ID).
It corresponds to the /proc/pid/task/tid/ path.
This field was removed in Linux 4.5, since
providing this information for a process with large
numbers of threads is expensive.
[vdso] The virtual dynamically linked shared object. See
vdso(7).
[heap] The process's heap.
[anon:name] (since Linux 5.17)
A named private anonymous mapping. Set with
prctl(2) PR_SET_VMA_ANON_NAME.
[anon_shmem:name] (since Linux 6.2)
A named shared anonymous mapping. Set with
prctl(2) PR_SET_VMA_ANON_NAME.
If the pathname field is blank, this is an anonymous
mapping as obtained via mmap(2). There is no easy way to
coordinate this back to a process's source, short of
running it through gdb(1), strace(1), or similar.
pathname is shown unescaped except for newline characters,
which are replaced with an octal escape sequence. As a
result, it is not possible to determine whether the
original pathname contained a newline character or the
literal \012 character sequence.
If the mapping is file-backed and the file has been
deleted, the string " (deleted)" is appended to the
pathname. Note that this is ambiguous too.
Under Linux 2.0, there is no field giving pathname.
proc(5)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-06-15 proc_pid_maps(5)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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