<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git, branch v4.19-rc8</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Linux 4.19-rc8</title>
<updated>2018-10-15T05:20:24+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2018-10-15T05:20:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=35a7f35ad1b150ddf59a41dcac7b2fa32982be0e'/>
<id>35a7f35ad1b150ddf59a41dcac7b2fa32982be0e</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'libnvdimm-fixes-4.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm</title>
<updated>2018-10-14T06:34:31+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2018-10-14T06:34:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3a27203102ebfa67bd0bced05b1def499bb59db2'/>
<id>3a27203102ebfa67bd0bced05b1def499bb59db2</id>
<content type='text'>
Dan writes:
  "libnvdimm/dax 4.19-rc8

   * Fix a livelock in dax_layout_busy_page() present since v4.18. The
     lockup triggers when truncating an actively mapped huge page out of
     a mapping pinned for direct-I/O.

   * Fix mprotect() clobbers of _PAGE_DEVMAP. Broken since v4.5
     mprotect() clears this flag that is needed to communicate the
     liveness of device pages to the get_user_pages() path."

* tag 'libnvdimm-fixes-4.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  mm: Preserve _PAGE_DEVMAP across mprotect() calls
  filesystem-dax: Fix dax_layout_busy_page() livelock
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Dan writes:
  "libnvdimm/dax 4.19-rc8

   * Fix a livelock in dax_layout_busy_page() present since v4.18. The
     lockup triggers when truncating an actively mapped huge page out of
     a mapping pinned for direct-I/O.

   * Fix mprotect() clobbers of _PAGE_DEVMAP. Broken since v4.5
     mprotect() clears this flag that is needed to communicate the
     liveness of device pages to the get_user_pages() path."

* tag 'libnvdimm-fixes-4.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  mm: Preserve _PAGE_DEVMAP across mprotect() calls
  filesystem-dax: Fix dax_layout_busy_page() livelock
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux</title>
<updated>2018-10-14T06:33:35+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2018-10-14T06:33:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a24a0eb9c8972803a8707041fc9ed9080cdaf1b9'/>
<id>a24a0eb9c8972803a8707041fc9ed9080cdaf1b9</id>
<content type='text'>
Wolfram writes:
  "i2c fix for 4.19:

   I2C has one documentation bugfix for something we changed during the
   v4.19 cycle"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: Fix kerneldoc for renamed i2c dma put function
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Wolfram writes:
  "i2c fix for 4.19:

   I2C has one documentation bugfix for something we changed during the
   v4.19 cycle"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: Fix kerneldoc for renamed i2c dma put function
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2018-10-13T13:11:15+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2018-10-13T13:11:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7ec21823634d7cb7ea20539b877c0d31830c6ad4'/>
<id>7ec21823634d7cb7ea20539b877c0d31830c6ad4</id>
<content type='text'>
Paolo writes:
  "KVM fixes for 4.19-rc8

   Leftover bugfixes."

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: vmx: hyper-v: don't pass EPT configuration info to vmx_hv_remote_flush_tlb()
  KVM: x86: support CONFIG_KVM_AMD=y with CONFIG_CRYPTO_DEV_CCP_DD=m
  ARM: KVM: Correctly order SGI register entries in the cp15 array
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Paolo writes:
  "KVM fixes for 4.19-rc8

   Leftover bugfixes."

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: vmx: hyper-v: don't pass EPT configuration info to vmx_hv_remote_flush_tlb()
  KVM: x86: support CONFIG_KVM_AMD=y with CONFIG_CRYPTO_DEV_CCP_DD=m
  ARM: KVM: Correctly order SGI register entries in the cp15 array
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: vmx: hyper-v: don't pass EPT configuration info to vmx_hv_remote_flush_tlb()</title>
<updated>2018-10-13T09:38:54+00:00</updated>
<author>
<name>Vitaly Kuznetsov</name>
<email>vkuznets@redhat.com</email>
</author>
<published>2018-10-11T10:03:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5f8bb004bca43f7b5043c02b4aa5b9b43e15fe50'/>
<id>5f8bb004bca43f7b5043c02b4aa5b9b43e15fe50</id>
<content type='text'>
I'm observing random crashes in multi-vCPU L2 guests running on KVM on
Hyper-V. I bisected the issue to the commit 877ad952be3d ("KVM: vmx: Add
tlb_remote_flush callback support"). Hyper-V TLFS states:

"AddressSpace specifies an address space ID (an EPT PML4 table pointer)"

So apparently, Hyper-V doesn't expect us to pass naked EPTP, only PML4
pointer should be used. Strip off EPT configuration information before
calling into vmx_hv_remote_flush_tlb().

Fixes: 877ad952be3d ("KVM: vmx: Add tlb_remote_flush callback support")
Signed-off-by: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
I'm observing random crashes in multi-vCPU L2 guests running on KVM on
Hyper-V. I bisected the issue to the commit 877ad952be3d ("KVM: vmx: Add
tlb_remote_flush callback support"). Hyper-V TLFS states:

"AddressSpace specifies an address space ID (an EPT PML4 table pointer)"

So apparently, Hyper-V doesn't expect us to pass naked EPTP, only PML4
pointer should be used. Strip off EPT configuration information before
calling into vmx_hv_remote_flush_tlb().

Fixes: 877ad952be3d ("KVM: vmx: Add tlb_remote_flush callback support")
Signed-off-by: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ubifs: Fix WARN_ON logic in exit path</title>
<updated>2018-10-13T09:05:02+00:00</updated>
<author>
<name>Richard Weinberger</name>
<email>richard@nod.at</email>
</author>
<published>2018-10-13T08:18:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f8ccb14fd6c9f58ef766062b7e3929c423580f09'/>
<id>f8ccb14fd6c9f58ef766062b7e3929c423580f09</id>
<content type='text'>
ubifs_assert() is not WARN_ON(), so we have to invert
the checks.
Randy faced this warning with UBIFS being a module, since
most users use UBIFS as builtin because UBIFS is the rootfs
nobody noticed so far. :-(
Including me.

Reported-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Fixes: 54169ddd382d ("ubifs: Turn two ubifs_assert() into a WARN_ON()")
Signed-off-by: Richard Weinberger &lt;richard@nod.at&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ubifs_assert() is not WARN_ON(), so we have to invert
the checks.
Randy faced this warning with UBIFS being a module, since
most users use UBIFS as builtin because UBIFS is the rootfs
nobody noticed so far. :-(
Including me.

Reported-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Fixes: 54169ddd382d ("ubifs: Turn two ubifs_assert() into a WARN_ON()")
Signed-off-by: Richard Weinberger &lt;richard@nod.at&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm'</title>
<updated>2018-10-13T07:31:19+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2018-10-13T07:31:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=79fc170b1f5c36f486d886bfbd59eb4e62321128'/>
<id>79fc170b1f5c36f486d886bfbd59eb4e62321128</id>
<content type='text'>
Fixes from Andrew:

* akpm:
  fs/fat/fatent.c: add cond_resched() to fat_count_free_clusters()
  mm/thp: fix call to mmu_notifier in set_pmd_migration_entry() v2
  mm/mmap.c: don't clobber partially overlapping VMA with MAP_FIXED_NOREPLACE
  ocfs2: fix a GCC warning
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fixes from Andrew:

* akpm:
  fs/fat/fatent.c: add cond_resched() to fat_count_free_clusters()
  mm/thp: fix call to mmu_notifier in set_pmd_migration_entry() v2
  mm/mmap.c: don't clobber partially overlapping VMA with MAP_FIXED_NOREPLACE
  ocfs2: fix a GCC warning
</pre>
</div>
</content>
</entry>
<entry>
<title>fs/fat/fatent.c: add cond_resched() to fat_count_free_clusters()</title>
<updated>2018-10-13T07:31:03+00:00</updated>
<author>
<name>Khazhismel Kumykov</name>
<email>khazhy@google.com</email>
</author>
<published>2018-10-13T04:34:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ac081c3be3fae6d0cc3e1862507fca3862d30b67'/>
<id>ac081c3be3fae6d0cc3e1862507fca3862d30b67</id>
<content type='text'>
On non-preempt kernels this loop can take a long time (more than 50 ticks)
processing through entries.

Link: http://lkml.kernel.org/r/20181010172623.57033-1-khazhy@google.com
Signed-off-by: Khazhismel Kumykov &lt;khazhy@google.com&gt;
Acked-by: OGAWA Hirofumi &lt;hirofumi@mail.parknet.co.jp&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On non-preempt kernels this loop can take a long time (more than 50 ticks)
processing through entries.

Link: http://lkml.kernel.org/r/20181010172623.57033-1-khazhy@google.com
Signed-off-by: Khazhismel Kumykov &lt;khazhy@google.com&gt;
Acked-by: OGAWA Hirofumi &lt;hirofumi@mail.parknet.co.jp&gt;
Reviewed-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/thp: fix call to mmu_notifier in set_pmd_migration_entry() v2</title>
<updated>2018-10-13T07:31:02+00:00</updated>
<author>
<name>Jérôme Glisse</name>
<email>jglisse@redhat.com</email>
</author>
<published>2018-10-13T04:34:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bfba8e5cf28f413aa05571af493871d74438979f'/>
<id>bfba8e5cf28f413aa05571af493871d74438979f</id>
<content type='text'>
Inside set_pmd_migration_entry() we are holding page table locks and thus
we can not sleep so we can not call invalidate_range_start/end()

So remove call to mmu_notifier_invalidate_range_start/end() because they
are call inside the function calling set_pmd_migration_entry() (see
try_to_unmap_one()).

Link: http://lkml.kernel.org/r/20181012181056.7864-1-jglisse@redhat.com
Signed-off-by: Jérôme Glisse &lt;jglisse@redhat.com&gt;
Reported-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Reviewed-by: Zi Yan &lt;zi.yan@cs.rutgers.edu&gt;
Acked-by: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Anshuman Khandual &lt;khandual@linux.vnet.ibm.com&gt;
Cc: Dave Hansen &lt;dave.hansen@intel.com&gt;
Cc: David Nellans &lt;dnellans@nvidia.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Inside set_pmd_migration_entry() we are holding page table locks and thus
we can not sleep so we can not call invalidate_range_start/end()

So remove call to mmu_notifier_invalidate_range_start/end() because they
are call inside the function calling set_pmd_migration_entry() (see
try_to_unmap_one()).

Link: http://lkml.kernel.org/r/20181012181056.7864-1-jglisse@redhat.com
Signed-off-by: Jérôme Glisse &lt;jglisse@redhat.com&gt;
Reported-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Reviewed-by: Zi Yan &lt;zi.yan@cs.rutgers.edu&gt;
Acked-by: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Anshuman Khandual &lt;khandual@linux.vnet.ibm.com&gt;
Cc: Dave Hansen &lt;dave.hansen@intel.com&gt;
Cc: David Nellans &lt;dnellans@nvidia.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/mmap.c: don't clobber partially overlapping VMA with MAP_FIXED_NOREPLACE</title>
<updated>2018-10-13T07:31:02+00:00</updated>
<author>
<name>Jann Horn</name>
<email>jannh@google.com</email>
</author>
<published>2018-10-13T04:34:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7aa867dd89526e9cfd9714d8b9b587c016eaea34'/>
<id>7aa867dd89526e9cfd9714d8b9b587c016eaea34</id>
<content type='text'>
Daniel Micay reports that attempting to use MAP_FIXED_NOREPLACE in an
application causes that application to randomly crash.  The existing check
for handling MAP_FIXED_NOREPLACE looks up the first VMA that either
overlaps or follows the requested region, and then bails out if that VMA
overlaps *the start* of the requested region.  It does not bail out if the
VMA only overlaps another part of the requested region.

Fix it by checking that the found VMA only starts at or after the end of
the requested region, in which case there is no overlap.

Test case:

user@debian:~$ cat mmap_fixed_simple.c
#include &lt;sys/mman.h&gt;
#include &lt;errno.h&gt;
#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;unistd.h&gt;

#ifndef MAP_FIXED_NOREPLACE
#define MAP_FIXED_NOREPLACE 0x100000
#endif

int main(void) {
  char *p;

  errno = 0;
  p = mmap((void*)0x10001000, 0x4000, PROT_NONE,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0);
  printf("p1=%p err=%m\n", p);

  errno = 0;
  p = mmap((void*)0x10000000, 0x2000, PROT_READ,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0);
  printf("p2=%p err=%m\n", p);

  char cmd[100];
  sprintf(cmd, "cat /proc/%d/maps", getpid());
  system(cmd);

  return 0;
}
user@debian:~$ gcc -o mmap_fixed_simple mmap_fixed_simple.c
user@debian:~$ ./mmap_fixed_simple
p1=0x10001000 err=Success
p2=0x10000000 err=Success
10000000-10002000 r--p 00000000 00:00 0
10002000-10005000 ---p 00000000 00:00 0
564a9a06f000-564a9a070000 r-xp 00000000 fe:01 264004
  /home/user/mmap_fixed_simple
564a9a26f000-564a9a270000 r--p 00000000 fe:01 264004
  /home/user/mmap_fixed_simple
564a9a270000-564a9a271000 rw-p 00001000 fe:01 264004
  /home/user/mmap_fixed_simple
564a9a54a000-564a9a56b000 rw-p 00000000 00:00 0                          [heap]
7f8eba447000-7f8eba5dc000 r-xp 00000000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba5dc000-7f8eba7dc000 ---p 00195000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba7dc000-7f8eba7e0000 r--p 00195000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba7e0000-7f8eba7e2000 rw-p 00199000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba7e2000-7f8eba7e6000 rw-p 00000000 00:00 0
7f8eba7e6000-7f8eba809000 r-xp 00000000 fe:01 405876
  /lib/x86_64-linux-gnu/ld-2.24.so
7f8eba9e9000-7f8eba9eb000 rw-p 00000000 00:00 0
7f8ebaa06000-7f8ebaa09000 rw-p 00000000 00:00 0
7f8ebaa09000-7f8ebaa0a000 r--p 00023000 fe:01 405876
  /lib/x86_64-linux-gnu/ld-2.24.so
7f8ebaa0a000-7f8ebaa0b000 rw-p 00024000 fe:01 405876
  /lib/x86_64-linux-gnu/ld-2.24.so
7f8ebaa0b000-7f8ebaa0c000 rw-p 00000000 00:00 0
7ffcc99fa000-7ffcc9a1b000 rw-p 00000000 00:00 0                          [stack]
7ffcc9b44000-7ffcc9b47000 r--p 00000000 00:00 0                          [vvar]
7ffcc9b47000-7ffcc9b49000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0
  [vsyscall]
user@debian:~$ uname -a
Linux debian 4.19.0-rc6+ #181 SMP Wed Oct 3 23:43:42 CEST 2018 x86_64 GNU/Linux
user@debian:~$

As you can see, the first page of the mapping at 0x10001000 was clobbered.

Link: http://lkml.kernel.org/r/20181010152736.99475-1-jannh@google.com
Fixes: a4ff8e8620d3 ("mm: introduce MAP_FIXED_NOREPLACE")
Signed-off-by: Jann Horn &lt;jannh@google.com&gt;
Reported-by: Daniel Micay &lt;danielmicay@gmail.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: John Hubbard &lt;jhubbard@nvidia.com&gt;
Acked-by: Kees Cook &lt;keescook@chromium.org&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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Daniel Micay reports that attempting to use MAP_FIXED_NOREPLACE in an
application causes that application to randomly crash.  The existing check
for handling MAP_FIXED_NOREPLACE looks up the first VMA that either
overlaps or follows the requested region, and then bails out if that VMA
overlaps *the start* of the requested region.  It does not bail out if the
VMA only overlaps another part of the requested region.

Fix it by checking that the found VMA only starts at or after the end of
the requested region, in which case there is no overlap.

Test case:

user@debian:~$ cat mmap_fixed_simple.c
#include &lt;sys/mman.h&gt;
#include &lt;errno.h&gt;
#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;unistd.h&gt;

#ifndef MAP_FIXED_NOREPLACE
#define MAP_FIXED_NOREPLACE 0x100000
#endif

int main(void) {
  char *p;

  errno = 0;
  p = mmap((void*)0x10001000, 0x4000, PROT_NONE,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0);
  printf("p1=%p err=%m\n", p);

  errno = 0;
  p = mmap((void*)0x10000000, 0x2000, PROT_READ,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0);
  printf("p2=%p err=%m\n", p);

  char cmd[100];
  sprintf(cmd, "cat /proc/%d/maps", getpid());
  system(cmd);

  return 0;
}
user@debian:~$ gcc -o mmap_fixed_simple mmap_fixed_simple.c
user@debian:~$ ./mmap_fixed_simple
p1=0x10001000 err=Success
p2=0x10000000 err=Success
10000000-10002000 r--p 00000000 00:00 0
10002000-10005000 ---p 00000000 00:00 0
564a9a06f000-564a9a070000 r-xp 00000000 fe:01 264004
  /home/user/mmap_fixed_simple
564a9a26f000-564a9a270000 r--p 00000000 fe:01 264004
  /home/user/mmap_fixed_simple
564a9a270000-564a9a271000 rw-p 00001000 fe:01 264004
  /home/user/mmap_fixed_simple
564a9a54a000-564a9a56b000 rw-p 00000000 00:00 0                          [heap]
7f8eba447000-7f8eba5dc000 r-xp 00000000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba5dc000-7f8eba7dc000 ---p 00195000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba7dc000-7f8eba7e0000 r--p 00195000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba7e0000-7f8eba7e2000 rw-p 00199000 fe:01 405885
  /lib/x86_64-linux-gnu/libc-2.24.so
7f8eba7e2000-7f8eba7e6000 rw-p 00000000 00:00 0
7f8eba7e6000-7f8eba809000 r-xp 00000000 fe:01 405876
  /lib/x86_64-linux-gnu/ld-2.24.so
7f8eba9e9000-7f8eba9eb000 rw-p 00000000 00:00 0
7f8ebaa06000-7f8ebaa09000 rw-p 00000000 00:00 0
7f8ebaa09000-7f8ebaa0a000 r--p 00023000 fe:01 405876
  /lib/x86_64-linux-gnu/ld-2.24.so
7f8ebaa0a000-7f8ebaa0b000 rw-p 00024000 fe:01 405876
  /lib/x86_64-linux-gnu/ld-2.24.so
7f8ebaa0b000-7f8ebaa0c000 rw-p 00000000 00:00 0
7ffcc99fa000-7ffcc9a1b000 rw-p 00000000 00:00 0                          [stack]
7ffcc9b44000-7ffcc9b47000 r--p 00000000 00:00 0                          [vvar]
7ffcc9b47000-7ffcc9b49000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0
  [vsyscall]
user@debian:~$ uname -a
Linux debian 4.19.0-rc6+ #181 SMP Wed Oct 3 23:43:42 CEST 2018 x86_64 GNU/Linux
user@debian:~$

As you can see, the first page of the mapping at 0x10001000 was clobbered.

Link: http://lkml.kernel.org/r/20181010152736.99475-1-jannh@google.com
Fixes: a4ff8e8620d3 ("mm: introduce MAP_FIXED_NOREPLACE")
Signed-off-by: Jann Horn &lt;jannh@google.com&gt;
Reported-by: Daniel Micay &lt;danielmicay@gmail.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: John Hubbard &lt;jhubbard@nvidia.com&gt;
Acked-by: Kees Cook &lt;keescook@chromium.org&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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