proc_pid_map_files(5)

🌸 NAME 🌸

/proc/pid/map_files/ — the memory-mapped files zone, bestie 💖

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✨ DESCRIPTION ✨

🗺️ /proc/pid/map_files/ (since Linux 3.3)

okay so this subdirectory is literally a lil guest list of every memory-mapped file, like the ones from mmap(2) 🫶

The entries are named by a memory region start and end address pair — expressed as hexadecimal numbers — and each one is a symbolic link pointing at the mapped file itself. iconic behavior honestly 💅

Here's the moment, with the output wrapped and reformatted to fit on an 80-column display:

# ls -l /proc/self/map_files/
lr-------- 1 root root 64 Apr 16 21:31
            3252e00000-3252e20000 -> /usr/lib64/ld-2.15.so
...

now… plot twist 🍓 Even though these entries are there for memory regions that got mapped with the MAP_FILE flag, the way anonymous shared memory (regions created with the MAP_ANON | MAP_SHARED flags) is implemented in Linux means those regions also show up in this directory. not them crashing the party 😭

Here's an example where the target file is the deleted /dev/zero one:

lrw------- 1 root root 64 Apr 16 21:33
            7fc075d2f000-7fc075e6f000 -> /dev/zero (deleted)

Permission to access this file is governed by a ptrace access mode PTRACE_MODE_READ_FSCREDS check — go peek at ptrace(2) for the deets 👑

⏳ heads up: until Linux 4.3, this directory only appeared if the CONFIG_CHECKPOINT_RESTORE kernel configuration option was enabled. so yeah, old kernels were gatekeeping 🙈

and now the capabilities part, because of course there's a permissions moment 💀 Capabilities are required to read the contents of the symbolic links in this directory:

• before Linux 5.9 — the reading process requires CAP_SYS_ADMIN in the initial user namespace
• since Linux 5.9 — the reading process must have either CAP_SYS_ADMIN or CAP_CHECKPOINT_RESTORE in the initial (i.e., root) user namespace

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🦋 SEE ALSO 🦋

• proc(5)

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and that's the whole vibe check, bestie 💜 this was the proc_pid_map_files(5) page from Linux man-pages 6.20, dated 2026-02-08 — go forth and map those files, you absolute main character 🌈✨👑