Did this issue start happening after an update/upgrade? Was there a
prior kernel version where you were not having this particular problem?
If it is a regression, we can perform a kernel bisect to narrow down
which commit introduced it.
Also, it might be good to test the latest mainline kernel to see if this
bug was already fixed upstream. If it was, can investigate to find the
commit that fixes the bug.
** Changed in: linux (Ubuntu)
Importance: Undecided => High
** Also affects: linux (Ubuntu Bionic)
Importance: Undecided
Status: New
** Also affects: pmdk (Ubuntu Bionic)
Importance: Undecided
Status: New
** Also affects: Ubuntu Bionic
Importance: Undecided
Status: New
** No longer affects: pmdk (Ubuntu Bionic)
** No longer affects: Ubuntu Bionic
** Changed in: linux (Ubuntu Bionic)
Status: New => Confirmed
** Changed in: linux (Ubuntu Bionic)
Importance: Undecided => High
** Changed in: linux (Ubuntu)
Assignee: (unassigned) => Joseph Salisbury (jsalisbury)
** Changed in: linux (Ubuntu Bionic)
Assignee: (unassigned) => Joseph Salisbury (jsalisbury)
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1799237
Title:
mprotect fails on ext4 with dax
Status in Ubuntu:
Invalid
Status in linux package in Ubuntu:
Confirmed
Status in pmdk package in Ubuntu:
Invalid
Status in linux source package in Bionic:
Confirmed
Bug description:
I have a file located on ext4 mounted with "dax". When I call mmap on that
file with protection flag different than PROT_NONE and pass the returned
address to mprotect(..., PROT_NONE) it fails with:
mprotect: Permission denied
This bug affects PMDK (https://github.com/pmem/pmdk) and seems to be Ubuntu
kernel-specific.
Problem was observer on kernel 4.15.0-36-generic and 4.15.0-34-generic
Below is a code which can be used to reproduce the issue.
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "usage %s file size\n",
argv[0]);
return 1;
}
int size = atoi(argv[2]);
int fd = open(argv[1], O_RDWR);
if (fd < 0) {
perror("open");
return 1;
}
void *addr = mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
if (addr == MAP_FAILED) {
perror("mmap");
return 1;
}
if(mprotect(addr, size, PROT_NONE)) {
perror("mprotect");
return 1;
}
return 0;
}
---
ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq',
'/dev/snd/timer'] failed with exit code 1:
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211
not found.
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2018-10-23 (0 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64
(20180725)
IwConfig:
lo no wireless extensions.
enp0s3 no wireless extensions.
Lsusb:
Bus 001 Device 002: ID 80ee:0021 VirtualBox USB Tablet
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: innotek GmbH VirtualBox
Package: linux (not installed)
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-36-generic
root=UUID=48e87c4c-3028-4252-b7bb-e1e6091ff7f6 ro quiet splash
ProcVersionSignature: Ubuntu 4.15.0-36.39-generic 4.15.18
RelatedPackageVersions:
linux-restricted-modules-4.15.0-36-generic N/A
linux-backports-modules-4.15.0-36-generic N/A
linux-firmware 1.173.1
RfKill:
Tags: bionic
Uname: Linux 4.15.0-36-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 12/01/2006
dmi.bios.vendor: innotek GmbH
dmi.bios.version: VirtualBox
dmi.board.name: VirtualBox
dmi.board.vendor: Oracle Corporation
dmi.board.version: 1.2
dmi.chassis.type: 1
dmi.chassis.vendor: Oracle Corporation
dmi.modalias:
dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr:
dmi.product.family: Virtual Machine
dmi.product.name: VirtualBox
dmi.product.version: 1.2
dmi.sys.vendor: innotek GmbH
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