PR_PAC_RESET_KEYS(2const)                            PR_PAC_RESET_KEYS(2const)

NAME
       PR_PAC_RESET_KEYS - reset the calling thread's pointer authentication
       code keys

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <linux/prctl.h>  /* Definition of PR_* constants */
       #include <sys/prctl.h>

       int prctl(PR_PAC_RESET_KEYS, unsigned long keys, 0L, 0L, 0L);

DESCRIPTION
       Securely reset the thread's pointer authentication keys to fresh random
       values generated by the kernel.

       The set of keys to be reset is specified by keys, which must be a
       logical OR of zero or more of the following:

       PR_PAC_APIAKEY
              instruction authentication key A

       PR_PAC_APIBKEY
              instruction authentication key B

       PR_PAC_APDAKEY
              data authentication key A

       PR_PAC_APDBKEY
              data authentication key B

       PR_PAC_APGAKEY
              generic authentication "A" key.

              (Yes folks, there really is no generic B key.)

       As a special case, if keys is zero, then all the keys are reset.  Since
       new keys could be added in future, this is the recommended way to
       completely wipe the existing keys when establishing a clean execution
       context.

       There is no need to use PR_PAC_RESET_KEYS in preparation for calling
       execve(2), since execve(2) resets all the pointer authentication keys.

RETURN VALUE
       On success, 0 is returned.  On error, -1 is returned, and errno is set
       to indicate the error.

ERRORS
       EINVAL keys contains set bits that are invalid or unsupported on this
              platform.

STANDARDS
       Linux.  arm64 only.

HISTORY
       Linux 5.0 (arm64).

CAVEATS
       Because the compiler or run-time environment may be using some or all
       of the keys, a successful PR_PAC_RESET_KEYS may crash the calling
       process.  The conditions for using it safely are complex and system-
       dependent.  Don't use it unless you know what you are doing.

SEE ALSO
       prctl(2)

       For more information, see the kernel source file
       Documentation/arch/arm64/pointer-authentication.rst.

Linux man-pages 6.19              2026-02-08         PR_PAC_RESET_KEYS(2const)