UFFDIO_POISON(2const) UFFDIO_POISON(2const)
NAME
UFFDIO_POISON - mark an address range as "poisoned"
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <linux/userfaultfd.h> /* Definition of UFFD* constants */
#include <sys/ioctl.h>
int ioctl(int fd, UFFDIO_POISON, ...);
#include <linux/userfaultfd.h>
struct uffdio_poison {
struct uffdio_range range;
/* Range to install poison PTE markers in */
__u64 mode; /* Flags controlling the behavior of poison */
__s64 updated; /* Number of bytes poisoned, or negated error */
};
DESCRIPTION
Mark an address range as "poisoned". Future accesses to these addresses
will raise a SIGBUS signal. Unlike MADV_HWPOISON this works by in-
stalling page table entries, rather than "really" poisoning the underly-
ing physical pages. This means it only affects this particular address
space.
The following value may be bitwise ORed in mode to change the behavior
of the UFFDIO_POISON operation:
UFFDIO_POISON_MODE_DONTWAKE
Do not wake up the thread that waits for page-fault resolution.
The updated field is used by the kernel to return the number of bytes
that were actually poisoned, or an error in the same manner as UFF-
DIO_COPY. If the value returned in the updated field doesn't match the
value that was specified in range.len, the operation fails with the er-
ror EAGAIN. The updated field is output-only; it is not read by the
UFFDIO_POISON operation.
RETURN VALUE
On success, 0 is returned. In this case, the entire area was poisoned.
On error, -1 is returned and errno is set to indicate the error.
ERRORS
EAGAIN The number of bytes mapped (i.e., the value returned in the up-
dated field) does not equal the value that was specified in the
range.len field.
EINVAL Either range.start or range.len was not a multiple of the system
page size; or range.len was zero; or the range specified was in-
valid.
EINVAL An invalid bit was specified in the mode field.
EEXIST One or more pages were already mapped in the given range.
ENOENT The faulting process has changed its virtual memory layout simul-
taneously with an outstanding UFFDIO_POISON operation.
ENOMEM Allocating memory for page table entries failed.
ESRCH The faulting process has exited at the time of a UFFDIO_POISON
operation.
STANDARDS
Linux.
HISTORY
Linux 6.6.
EXAMPLES
See userfaultfd(2).
SEE ALSO
ioctl(2), ioctl_userfaultfd(2), userfaultfd(2)
linux.git/Documentation/admin-guide/mm/userfaultfd.rst
Linux man-pages 6.9.1 2024-06-17 UFFDIO_POISON(2const)
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