Hello,
I''m using xen 4.1.2 and I try to shared memory pages between the dom0
and
domU''s. For that purpose, I looked at gntalloc and gntdev. To test
these
modules, I created two programs :
- gntalloc_test : a program running in dom0 and granting some pages to a
domU and putting random values in it.
- gntdev_test : a program running in the domU, mapping the granted pages
and reading the values contained in it.
I succeeded in transferring values from dom0 to domU, but I have a Bad page
map error when the program in domU exits :
[ 123.903755] BUG: Bad page map in process test pte:80000000107ff167
pmd:0c7e3067
[ 123.903765] page:ffffea000041ffc0 count:0 mapcount:-1 mapping:
(null) index:0xffff88000e56b500
[ 123.903899] page flags:
0x100000000000c14(referenced|dirty|reserved|private)
[ 123.903910] addr:00007f9845c3d000 vm_flags:000e00fb anon_vma:
(null) mapping:ffff88000d637668 index:0
[ 123.903920] vma->vm_ops->fault: 0x0
[ 123.903924] vma->vm_file->f_op->mmap: gntdev_mmap+0x0/0x290
[xen_gntdev]
If I run several times gntdev_test, the count and the mapcount keeps
decreasing :
[ 125.144693] page:ffffea000041ffc0 count:-1 mapcount:-2 mapping:
(null) index:0xffff88000e56b720
[ 126.072717] page:ffffea000041ffc0 count:-2 mapcount:-3 mapping:
(null) index:0xffff88000e56b7c0
The error message coming from dmesg is :
[ 126.072703] BUG: Bad page map in process test pte:80000000107ff167
pmd:0e6a2067
[ 126.072717] page:ffffea000041ffc0 count:-2 mapcount:-3 mapping:
(null) index:0xffff88000e56b7c0
[ 126.072724] page flags:
0x100000000000c14(referenced|dirty|reserved|private)
[ 126.072739] addr:00007ff931aec000 vm_flags:000e00fb anon_vma:
(null) mapping:ffff88000d637668 index:0
[ 126.072749] vma->vm_ops->fault: 0x0
[ 126.072754] vma->vm_file->f_op->mmap: gntdev_mmap+0x0/0x290
[xen_gntdev]
[ 126.072761] Pid: 1268, comm: test Tainted: G B W
3.2.0-34-generic #53-Ubuntu
[ 126.072764] Call Trace:
[ 126.072769] [<ffffffff81139c99>] print_bad_pte+0x1d9/0x270
[ 126.072772] [<ffffffff8113c799>] zap_pte_range+0x369/0x3d0
[ 126.072775] [<ffffffff81005339>] ?
__raw_callee_save_xen_pmd_val+0x11/0x1e
[ 126.072779] [<ffffffff8113c9aa>] unmap_page_range+0x1aa/0x300
[ 126.072782] [<ffffffff8113d08a>] unmap_vmas+0xca/0x1a0
[ 126.072785] [<ffffffff81144607>] exit_mmap+0x97/0x140
[ 126.072788] [<ffffffff8113dde8>] ? handle_mm_fault+0x1f8/0x350
[ 126.072792] [<ffffffff8165bfde>] ?
_raw_spin_unlock_irqrestore+0x1e/0x30
[ 126.072795] [<ffffffff81064b92>] mmput.part.16+0x42/0x130
[ 126.072798] [<ffffffff81064ca9>] mmput+0x29/0x30
[ 126.072802] [<ffffffff8106b603>] exit_mm+0x113/0x130
[ 126.072806] [<ffffffff810e41c5>] ? taskstats_exit+0x45/0x240
[ 126.072809] [<ffffffff8165c0b5>] ? _raw_spin_lock_irq+0x15/0x20
[ 126.072812] [<ffffffff8106b78e>] do_exit+0x16e/0x450
[ 126.072817] [<ffffffff811783e0>] ? vfs_write+0x110/0x180
[ 126.072820] [<ffffffff8106bc14>] do_group_exit+0x44/0xa0
[ 126.072823] [<ffffffff8106bc87>] sys_exit_group+0x17/0x20
[ 126.072826] [<ffffffff816643c2>] system_call_fastpath+0x16/0x1b
Here are the codes of the two programs :
gntalloc_test.c :
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <xen/gntalloc.h>
#include <linux/ioctl.h>
int main(){
int fd = open("/dev/xen/gntalloc", O_RDWR);
if(fd == -1){
perror("Open : ");
return -1;
}
struct ioctl_gntalloc_alloc_gref arg;
arg.domid = 5;
arg.flags = GNTALLOC_FLAG_WRITABLE;
arg.count = 4;
ioctl(fd, IOCTL_GNTALLOC_ALLOC_GREF, &arg);
int i;
for(i=0; i<4;++i)
printf("Gref : %d\n", arg.gref_ids[i]);
struct ioctl_gntalloc_dealloc_gref dearg;
dearg.index = arg.index;
dearg.count = arg.count;
int * vadr = mmap(0, getpagesize(), PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
vadr[0]=1337;
vadr[1]=20057;
vadr[2]=9000;
int wait;
printf("vadr : %d %d %d\nEn attente ...\n", vadr[0], vadr[1],
vadr[2]);
scanf("%d", &wait);
ioctl(fd, IOCTL_GNTALLOC_DEALLOC_GREF, &dearg);
}
gntdev_test.c :
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <xen/gntdev.h>
#include <linux/ioctl.h>
int main(){
int fd;
if((fd = open("/dev/xen/gntdev2", O_RDWR))==-1){
perror("open");
return;
}
struct ioctl_gntdev_map_grant_ref arg;
struct ioctl_gntdev_unmap_grant_ref dearg[2];
arg.count = 1;
arg.refs[0].ref=32;
arg.refs[0].domid=0;
ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg);
dearg[0].index = arg.index;
dearg[0].count = arg.count;
arg.refs[0].ref=33;
ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg);
printf("Index in the file : %ld\n", arg.index);
int * vaddr;
if((vaddr = mmap(0, getpagesize(), PROT_READ | PROT_WRITE,
MAP_SHARED, f
d, 0))==NULL)
return;
printf("Vaddr : %d %d %d\n", vaddr[0], vaddr[1], vaddr[2]);
dearg[1].index = arg.index;
dearg[1].count = arg.count;
printf("First grant\n");
ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &dearg[0]);
printf("Second grant\n");
ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &dearg[1]);
printf("The end\n");
}
I tried to track where the error comes from. When I execute gntdev_test,
the error message is displayed after the final message (The end) ; if I
look dmesg I can see than :
- The first page is "unmapped"
- The second page is "unmapped"
- The second page is freed
- The error happens
- gntdev_vma_close is called
- The first page is freed
I used a modified version of the module to track these steps, but the
original module
(/lib/modules/3.2.0-34-generic/kernel/drivers/xen/xen-gntdev.ko) gives the
same error.
I suppose that something is missing in gntdev_test.c to manage the mapping
of pages but I don''t know what. I tried to call the unmap function, but
it''s worst as it adds other errors.
Does someone know what''s missing please ?
Best regards,
Frémal Sébastien
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
On Tue, Mar 26, 2013 at 05:32:00PM +0100, Sébastien Frémal wrote:> Hello, > > I''m using xen 4.1.2 and I try to shared memory pages between the dom0 and > domU''s. For that purpose, I looked at gntalloc and gntdev. To test these > modules, I created two programs :You are using an older kernel - and there wer some updates in the gntalloc/gntdev driver. Do you see this when you use an updated kernel?> > - gntalloc_test : a program running in dom0 and granting some pages to a > domU and putting random values in it. > - gntdev_test : a program running in the domU, mapping the granted pages > and reading the values contained in it. > > I succeeded in transferring values from dom0 to domU, but I have a Bad page > map error when the program in domU exits : > > [ 123.903755] BUG: Bad page map in process test pte:80000000107ff167 > pmd:0c7e3067 > [ 123.903765] page:ffffea000041ffc0 count:0 mapcount:-1 mapping: > (null) index:0xffff88000e56b500 > [ 123.903899] page flags: > 0x100000000000c14(referenced|dirty|reserved|private) > [ 123.903910] addr:00007f9845c3d000 vm_flags:000e00fb anon_vma: > (null) mapping:ffff88000d637668 index:0 > [ 123.903920] vma->vm_ops->fault: 0x0 > [ 123.903924] vma->vm_file->f_op->mmap: gntdev_mmap+0x0/0x290 [xen_gntdev] > > If I run several times gntdev_test, the count and the mapcount keeps > decreasing : > > [ 125.144693] page:ffffea000041ffc0 count:-1 mapcount:-2 mapping: > (null) index:0xffff88000e56b720 > [ 126.072717] page:ffffea000041ffc0 count:-2 mapcount:-3 mapping: > (null) index:0xffff88000e56b7c0 > > The error message coming from dmesg is : > > [ 126.072703] BUG: Bad page map in process test pte:80000000107ff167 > pmd:0e6a2067 > [ 126.072717] page:ffffea000041ffc0 count:-2 mapcount:-3 mapping: > (null) index:0xffff88000e56b7c0 > [ 126.072724] page flags: > 0x100000000000c14(referenced|dirty|reserved|private) > [ 126.072739] addr:00007ff931aec000 vm_flags:000e00fb anon_vma: > (null) mapping:ffff88000d637668 index:0 > [ 126.072749] vma->vm_ops->fault: 0x0 > [ 126.072754] vma->vm_file->f_op->mmap: gntdev_mmap+0x0/0x290 [xen_gntdev] > [ 126.072761] Pid: 1268, comm: test Tainted: G B W > 3.2.0-34-generic #53-Ubuntu > [ 126.072764] Call Trace: > [ 126.072769] [<ffffffff81139c99>] print_bad_pte+0x1d9/0x270 > [ 126.072772] [<ffffffff8113c799>] zap_pte_range+0x369/0x3d0 > [ 126.072775] [<ffffffff81005339>] ? > __raw_callee_save_xen_pmd_val+0x11/0x1e > [ 126.072779] [<ffffffff8113c9aa>] unmap_page_range+0x1aa/0x300 > [ 126.072782] [<ffffffff8113d08a>] unmap_vmas+0xca/0x1a0 > [ 126.072785] [<ffffffff81144607>] exit_mmap+0x97/0x140 > [ 126.072788] [<ffffffff8113dde8>] ? handle_mm_fault+0x1f8/0x350 > [ 126.072792] [<ffffffff8165bfde>] ? _raw_spin_unlock_irqrestore+0x1e/0x30 > [ 126.072795] [<ffffffff81064b92>] mmput.part.16+0x42/0x130 > [ 126.072798] [<ffffffff81064ca9>] mmput+0x29/0x30 > [ 126.072802] [<ffffffff8106b603>] exit_mm+0x113/0x130 > [ 126.072806] [<ffffffff810e41c5>] ? taskstats_exit+0x45/0x240 > [ 126.072809] [<ffffffff8165c0b5>] ? _raw_spin_lock_irq+0x15/0x20 > [ 126.072812] [<ffffffff8106b78e>] do_exit+0x16e/0x450 > [ 126.072817] [<ffffffff811783e0>] ? vfs_write+0x110/0x180 > [ 126.072820] [<ffffffff8106bc14>] do_group_exit+0x44/0xa0 > [ 126.072823] [<ffffffff8106bc87>] sys_exit_group+0x17/0x20 > [ 126.072826] [<ffffffff816643c2>] system_call_fastpath+0x16/0x1b > > Here are the codes of the two programs : > > gntalloc_test.c : > > #include <stdio.h> > #include <stdint.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <sys/mman.h> > #include <fcntl.h> > #include <xen/gntalloc.h> > #include <linux/ioctl.h> > > int main(){ > int fd = open("/dev/xen/gntalloc", O_RDWR); > if(fd == -1){ > perror("Open : "); > return -1; > } > struct ioctl_gntalloc_alloc_gref arg; > arg.domid = 5; > arg.flags = GNTALLOC_FLAG_WRITABLE; > arg.count = 4; > ioctl(fd, IOCTL_GNTALLOC_ALLOC_GREF, &arg); > int i; > for(i=0; i<4;++i) > printf("Gref : %d\n", arg.gref_ids[i]); > struct ioctl_gntalloc_dealloc_gref dearg; > dearg.index = arg.index; > dearg.count = arg.count; > int * vadr = mmap(0, getpagesize(), PROT_READ | PROT_WRITE, > MAP_SHARED, fd, 0); > vadr[0]=1337; > vadr[1]=20057; > vadr[2]=9000; > int wait; > printf("vadr : %d %d %d\nEn attente ...\n", vadr[0], vadr[1], > vadr[2]); > scanf("%d", &wait); > ioctl(fd, IOCTL_GNTALLOC_DEALLOC_GREF, &dearg); > } > > gntdev_test.c : > > #include <stdio.h> > #include <stdint.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <sys/mman.h> > #include <fcntl.h> > #include <xen/gntdev.h> > #include <linux/ioctl.h> > > int main(){ > int fd; > if((fd = open("/dev/xen/gntdev2", O_RDWR))==-1){ > perror("open"); > return; > } > struct ioctl_gntdev_map_grant_ref arg; > struct ioctl_gntdev_unmap_grant_ref dearg[2]; > arg.count = 1; > arg.refs[0].ref=32; > arg.refs[0].domid=0; > ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg); > dearg[0].index = arg.index; > dearg[0].count = arg.count; > arg.refs[0].ref=33; > ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg); > printf("Index in the file : %ld\n", arg.index); > int * vaddr; > if((vaddr = mmap(0, getpagesize(), PROT_READ | PROT_WRITE, > MAP_SHARED, f > d, 0))==NULL) > return; > printf("Vaddr : %d %d %d\n", vaddr[0], vaddr[1], vaddr[2]); > > dearg[1].index = arg.index; > dearg[1].count = arg.count; > printf("First grant\n"); > ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &dearg[0]); > printf("Second grant\n"); > ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &dearg[1]); > printf("The end\n"); > } > > I tried to track where the error comes from. When I execute gntdev_test, > the error message is displayed after the final message (The end) ; if I > look dmesg I can see than : > - The first page is "unmapped" > - The second page is "unmapped" > - The second page is freed > - The error happens > - gntdev_vma_close is called > - The first page is freed > I used a modified version of the module to track these steps, but the > original module > (/lib/modules/3.2.0-34-generic/kernel/drivers/xen/xen-gntdev.ko) gives the > same error. > > I suppose that something is missing in gntdev_test.c to manage the mapping > of pages but I don''t know what. I tried to call the unmap function, but > it''s worst as it adds other errors. > > Does someone know what''s missing please ? > > Best regards, > > Frémal Sébastien> _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel
Hello, I upgraded my Linux kernel (3.2 -> 3.5) and my Xen version (4.1.2 -> 4.2.1) but I have problems with xen-create-image. I installed Xen (as explained here : http://locatrix.com/build-and-install-xen-4-2-1-from-source-on-ubuntu-12-10/) but xen-tools wasn''t installed (I got the message : xen-create-image: command not found). I searched for a solution, and the only one I found was to install it with apt-get. apt-get installed xen-tools, some other xen 4.1.2 packages and failed to install some other packages because there were conflicts with packages of xen 4.2.1. I tried to create a new virtual machine to get a newer kernel, but there were problems while executing xen-create-image : hook 80-install-kernel failed: 256 Running command ''xt-customize-image --dist=squeeze --location=/tmp/_XR3BFfEHU 2>&1'' failed with exit code 256. As it didn''t work, I deleted 4.1.2 xen packages (as I want to work with the 4.2.1 version and that it doesn''t solve the problem) and the error message coming from xen-create-image also changed : Installation method: debootstrap Done System installation failed. Aborting /tmp/L2E_5moWml/etc/ssh/ssh_host_rsa_key.pub: No such file or directory Running command ''umount /tmp/L2E_5moWml/proc 2>&1'' failed with exit code 256. Aborting Presently, my virtual machine is still running with a 3.2 linux kernel, I can''t compile the file gntdev.c written for the 3.5 linux kernel (found here : http://www.filewatcher.com/p/linux-3.5-rc6.tar.bz2.80960577/linux-3.5-rc6/drivers/xen/gntdev.c.html) because functions have changed and I can''t create a new virtual machine as xen-tools (and more specifically xen-create-image) can''t be found if installed from sources. I looked inside of the package xen-upstream-4.2.1.deb and I didn''t find any file like "xen-create-image". Do you know how to properly install xen-tools from Xen 4.2.1 sources so I can test gntdev with a newer kernel please ? Best regards, Sébastien Frémal 2013/3/26 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>> On Tue, Mar 26, 2013 at 05:32:00PM +0100, Sébastien Frémal wrote: > > Hello, > > > > I''m using xen 4.1.2 and I try to shared memory pages between the dom0 and > > domU''s. For that purpose, I looked at gntalloc and gntdev. To test these > > modules, I created two programs : > > You are using an older kernel - and there wer some updates in the > gntalloc/gntdev > driver. Do you see this when you use an updated kernel? > > > > - gntalloc_test : a program running in dom0 and granting some pages > to a > > domU and putting random values in it. > > - gntdev_test : a program running in the domU, mapping the granted > pages > > and reading the values contained in it. > > > > I succeeded in transferring values from dom0 to domU, but I have a Bad > page > > map error when the program in domU exits : > > > > [ 123.903755] BUG: Bad page map in process test pte:80000000107ff167 > > pmd:0c7e3067 > > [ 123.903765] page:ffffea000041ffc0 count:0 mapcount:-1 mapping: > > (null) index:0xffff88000e56b500 > > [ 123.903899] page flags: > > 0x100000000000c14(referenced|dirty|reserved|private) > > [ 123.903910] addr:00007f9845c3d000 vm_flags:000e00fb anon_vma: > > (null) mapping:ffff88000d637668 index:0 > > [ 123.903920] vma->vm_ops->fault: 0x0 > > [ 123.903924] vma->vm_file->f_op->mmap: gntdev_mmap+0x0/0x290 > [xen_gntdev] > > > > If I run several times gntdev_test, the count and the mapcount keeps > > decreasing : > > > > [ 125.144693] page:ffffea000041ffc0 count:-1 mapcount:-2 mapping: > > (null) index:0xffff88000e56b720 > > [ 126.072717] page:ffffea000041ffc0 count:-2 mapcount:-3 mapping: > > (null) index:0xffff88000e56b7c0 > > > > The error message coming from dmesg is : > > > > [ 126.072703] BUG: Bad page map in process test pte:80000000107ff167 > > pmd:0e6a2067 > > [ 126.072717] page:ffffea000041ffc0 count:-2 mapcount:-3 mapping: > > (null) index:0xffff88000e56b7c0 > > [ 126.072724] page flags: > > 0x100000000000c14(referenced|dirty|reserved|private) > > [ 126.072739] addr:00007ff931aec000 vm_flags:000e00fb anon_vma: > > (null) mapping:ffff88000d637668 index:0 > > [ 126.072749] vma->vm_ops->fault: 0x0 > > [ 126.072754] vma->vm_file->f_op->mmap: gntdev_mmap+0x0/0x290 > [xen_gntdev] > > [ 126.072761] Pid: 1268, comm: test Tainted: G B W > > 3.2.0-34-generic #53-Ubuntu > > [ 126.072764] Call Trace: > > [ 126.072769] [<ffffffff81139c99>] print_bad_pte+0x1d9/0x270 > > [ 126.072772] [<ffffffff8113c799>] zap_pte_range+0x369/0x3d0 > > [ 126.072775] [<ffffffff81005339>] ? > > __raw_callee_save_xen_pmd_val+0x11/0x1e > > [ 126.072779] [<ffffffff8113c9aa>] unmap_page_range+0x1aa/0x300 > > [ 126.072782] [<ffffffff8113d08a>] unmap_vmas+0xca/0x1a0 > > [ 126.072785] [<ffffffff81144607>] exit_mmap+0x97/0x140 > > [ 126.072788] [<ffffffff8113dde8>] ? handle_mm_fault+0x1f8/0x350 > > [ 126.072792] [<ffffffff8165bfde>] ? > _raw_spin_unlock_irqrestore+0x1e/0x30 > > [ 126.072795] [<ffffffff81064b92>] mmput.part.16+0x42/0x130 > > [ 126.072798] [<ffffffff81064ca9>] mmput+0x29/0x30 > > [ 126.072802] [<ffffffff8106b603>] exit_mm+0x113/0x130 > > [ 126.072806] [<ffffffff810e41c5>] ? taskstats_exit+0x45/0x240 > > [ 126.072809] [<ffffffff8165c0b5>] ? _raw_spin_lock_irq+0x15/0x20 > > [ 126.072812] [<ffffffff8106b78e>] do_exit+0x16e/0x450 > > [ 126.072817] [<ffffffff811783e0>] ? vfs_write+0x110/0x180 > > [ 126.072820] [<ffffffff8106bc14>] do_group_exit+0x44/0xa0 > > [ 126.072823] [<ffffffff8106bc87>] sys_exit_group+0x17/0x20 > > [ 126.072826] [<ffffffff816643c2>] system_call_fastpath+0x16/0x1b > > > > Here are the codes of the two programs : > > > > gntalloc_test.c : > > > > #include <stdio.h> > > #include <stdint.h> > > #include <sys/types.h> > > #include <sys/stat.h> > > #include <sys/mman.h> > > #include <fcntl.h> > > #include <xen/gntalloc.h> > > #include <linux/ioctl.h> > > > > int main(){ > > int fd = open("/dev/xen/gntalloc", O_RDWR); > > if(fd == -1){ > > perror("Open : "); > > return -1; > > } > > struct ioctl_gntalloc_alloc_gref arg; > > arg.domid = 5; > > arg.flags = GNTALLOC_FLAG_WRITABLE; > > arg.count = 4; > > ioctl(fd, IOCTL_GNTALLOC_ALLOC_GREF, &arg); > > int i; > > for(i=0; i<4;++i) > > printf("Gref : %d\n", arg.gref_ids[i]); > > struct ioctl_gntalloc_dealloc_gref dearg; > > dearg.index = arg.index; > > dearg.count = arg.count; > > int * vadr = mmap(0, getpagesize(), PROT_READ | PROT_WRITE, > > MAP_SHARED, fd, 0); > > vadr[0]=1337; > > vadr[1]=20057; > > vadr[2]=9000; > > int wait; > > printf("vadr : %d %d %d\nEn attente ...\n", vadr[0], vadr[1], > > vadr[2]); > > scanf("%d", &wait); > > ioctl(fd, IOCTL_GNTALLOC_DEALLOC_GREF, &dearg); > > } > > > > gntdev_test.c : > > > > #include <stdio.h> > > #include <stdint.h> > > #include <sys/types.h> > > #include <sys/stat.h> > > #include <sys/mman.h> > > #include <fcntl.h> > > #include <xen/gntdev.h> > > #include <linux/ioctl.h> > > > > int main(){ > > int fd; > > if((fd = open("/dev/xen/gntdev2", O_RDWR))==-1){ > > perror("open"); > > return; > > } > > struct ioctl_gntdev_map_grant_ref arg; > > struct ioctl_gntdev_unmap_grant_ref dearg[2]; > > arg.count = 1; > > arg.refs[0].ref=32; > > arg.refs[0].domid=0; > > ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg); > > dearg[0].index = arg.index; > > dearg[0].count = arg.count; > > arg.refs[0].ref=33; > > ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg); > > printf("Index in the file : %ld\n", arg.index); > > int * vaddr; > > if((vaddr = mmap(0, getpagesize(), PROT_READ | PROT_WRITE, > > MAP_SHARED, f > > d, 0))==NULL) > > return; > > printf("Vaddr : %d %d %d\n", vaddr[0], vaddr[1], vaddr[2]); > > > > dearg[1].index = arg.index; > > dearg[1].count = arg.count; > > printf("First grant\n"); > > ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &dearg[0]); > > printf("Second grant\n"); > > ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &dearg[1]); > > printf("The end\n"); > > } > > > > I tried to track where the error comes from. When I execute gntdev_test, > > the error message is displayed after the final message (The end) ; if I > > look dmesg I can see than : > > - The first page is "unmapped" > > - The second page is "unmapped" > > - The second page is freed > > - The error happens > > - gntdev_vma_close is called > > - The first page is freed > > I used a modified version of the module to track these steps, but the > > original module > > (/lib/modules/3.2.0-34-generic/kernel/drivers/xen/xen-gntdev.ko) gives > the > > same error. > > > > I suppose that something is missing in gntdev_test.c to manage the > mapping > > of pages but I don''t know what. I tried to call the unmap function, but > > it''s worst as it adds other errors. > > > > Does someone know what''s missing please ? > > > > Best regards, > > > > Frémal Sébastien > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xen.org > > http://lists.xen.org/xen-devel > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Hello, I finally found and installed sources of xen-tools. I created a virtual machine with a linux kernel of version 3.5 but I still have a Bad page map error with a decrease of the value of the variables "count" and "mapcount". I will search to have access to these variables in the module and monitor their value during the execution of the program to identify what''s going wrong. Best regards, Sébastien Frémal _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Finally, I used the v3.8 kernel on my computer and for the virtual machine. The "channel" gntalloc + gntdev works now. I didn''t discover what was the bug with the previous versions of the kernel. Thank you for your help and indications. Best regards, Sebastien Fremal _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel