<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git, branch v5.7.6</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Linux 5.7.6</title>
<updated>2020-06-24T15:49:26+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2020-06-24T15:49:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a06eb423367eea436351ef2a92f61a4e625cf558'/>
<id>a06eb423367eea436351ef2a92f61a4e625cf558</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>iommu/vt-d: Remove real DMA lookup in find_domain</title>
<updated>2020-06-24T15:49:26+00:00</updated>
<author>
<name>Jon Derrick</name>
<email>jonathan.derrick@intel.com</email>
</author>
<published>2020-05-27T16:56:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=94621ff43f69c71876bc0a4bade550ea996d6cb2'/>
<id>94621ff43f69c71876bc0a4bade550ea996d6cb2</id>
<content type='text'>
commit bba9cc2cf82840bd3c9b3f4f7edac2dc8329c241 upstream.

By removing the real DMA indirection in find_domain(), we can allow
sub-devices of a real DMA device to have their own valid
device_domain_info. The dmar lookup and context entry removal paths have
been fixed to account for sub-devices.

Fixes: 2b0140c69637 ("iommu/vt-d: Use pci_real_dma_dev() for mapping")
Signed-off-by: Jon Derrick &lt;jonathan.derrick@intel.com&gt;
Acked-by: Lu Baolu &lt;baolu.lu@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20200527165617.297470-4-jonathan.derrick@intel.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207575
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
Signed-off-by: Sushma Kalakota &lt;sushmax.kalakota@intel.com&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>
commit bba9cc2cf82840bd3c9b3f4f7edac2dc8329c241 upstream.

By removing the real DMA indirection in find_domain(), we can allow
sub-devices of a real DMA device to have their own valid
device_domain_info. The dmar lookup and context entry removal paths have
been fixed to account for sub-devices.

Fixes: 2b0140c69637 ("iommu/vt-d: Use pci_real_dma_dev() for mapping")
Signed-off-by: Jon Derrick &lt;jonathan.derrick@intel.com&gt;
Acked-by: Lu Baolu &lt;baolu.lu@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20200527165617.297470-4-jonathan.derrick@intel.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207575
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
Signed-off-by: Sushma Kalakota &lt;sushmax.kalakota@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: core: device_rename: Use rwsem instead of a seqcount</title>
<updated>2020-06-24T15:49:26+00:00</updated>
<author>
<name>Ahmed S. Darwish</name>
<email>a.darwish@linutronix.de</email>
</author>
<published>2020-06-03T14:49:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ebd56ab72b531b696061c057f4d63b9ddd8375da'/>
<id>ebd56ab72b531b696061c057f4d63b9ddd8375da</id>
<content type='text'>
commit 11d6011c2cf29f7c8181ebde6c8bc0c4d83adcd7 upstream.

Sequence counters write paths are critical sections that must never be
preempted, and blocking, even for CONFIG_PREEMPTION=n, is not allowed.

Commit 5dbe7c178d3f ("net: fix kernel deadlock with interface rename and
netdev name retrieval.") handled a deadlock, observed with
CONFIG_PREEMPTION=n, where the devnet_rename seqcount read side was
infinitely spinning: it got scheduled after the seqcount write side
blocked inside its own critical section.

To fix that deadlock, among other issues, the commit added a
cond_resched() inside the read side section. While this will get the
non-preemptible kernel eventually unstuck, the seqcount reader is fully
exhausting its slice just spinning -- until TIF_NEED_RESCHED is set.

The fix is also still broken: if the seqcount reader belongs to a
real-time scheduling policy, it can spin forever and the kernel will
livelock.

Disabling preemption over the seqcount write side critical section will
not work: inside it are a number of GFP_KERNEL allocations and mutex
locking through the drivers/base/ :: device_rename() call chain.

&gt;From all the above, replace the seqcount with a rwsem.

Fixes: 5dbe7c178d3f (net: fix kernel deadlock with interface rename and netdev name retrieval.)
Fixes: 30e6c9fa93cf (net: devnet_rename_seq should be a seqcount)
Fixes: c91f6df2db49 (sockopt: Change getsockopt() of SO_BINDTODEVICE to return an interface name)
Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: kbuild test robot &lt;lkp@intel.com&gt; [ v1 missing up_read() on error exit ]
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt; [ v1 missing up_read() on error exit ]
Signed-off-by: Ahmed S. Darwish &lt;a.darwish@linutronix.de&gt;
Reviewed-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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>
commit 11d6011c2cf29f7c8181ebde6c8bc0c4d83adcd7 upstream.

Sequence counters write paths are critical sections that must never be
preempted, and blocking, even for CONFIG_PREEMPTION=n, is not allowed.

Commit 5dbe7c178d3f ("net: fix kernel deadlock with interface rename and
netdev name retrieval.") handled a deadlock, observed with
CONFIG_PREEMPTION=n, where the devnet_rename seqcount read side was
infinitely spinning: it got scheduled after the seqcount write side
blocked inside its own critical section.

To fix that deadlock, among other issues, the commit added a
cond_resched() inside the read side section. While this will get the
non-preemptible kernel eventually unstuck, the seqcount reader is fully
exhausting its slice just spinning -- until TIF_NEED_RESCHED is set.

The fix is also still broken: if the seqcount reader belongs to a
real-time scheduling policy, it can spin forever and the kernel will
livelock.

Disabling preemption over the seqcount write side critical section will
not work: inside it are a number of GFP_KERNEL allocations and mutex
locking through the drivers/base/ :: device_rename() call chain.

&gt;From all the above, replace the seqcount with a rwsem.

Fixes: 5dbe7c178d3f (net: fix kernel deadlock with interface rename and netdev name retrieval.)
Fixes: 30e6c9fa93cf (net: devnet_rename_seq should be a seqcount)
Fixes: c91f6df2db49 (sockopt: Change getsockopt() of SO_BINDTODEVICE to return an interface name)
Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: kbuild test robot &lt;lkp@intel.com&gt; [ v1 missing up_read() on error exit ]
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt; [ v1 missing up_read() on error exit ]
Signed-off-by: Ahmed S. Darwish &lt;a.darwish@linutronix.de&gt;
Reviewed-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: octeon: mgmt: Repair filling of RX ring</title>
<updated>2020-06-24T15:49:26+00:00</updated>
<author>
<name>Alexander Sverdlin</name>
<email>alexander.sverdlin@nokia.com</email>
</author>
<published>2020-05-29T12:17:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fd9757bb7044b1d01009240d0807a026b9c64038'/>
<id>fd9757bb7044b1d01009240d0807a026b9c64038</id>
<content type='text'>
commit 0c34bb598c510e070160029f34efeeb217000f8d upstream.

The removal of mips_swiotlb_ops exposed a problem in octeon_mgmt Ethernet
driver. mips_swiotlb_ops had an mb() after most of the operations and the
removal of the ops had broken the receive functionality of the driver.
My code inspection has shown no other places except
octeon_mgmt_rx_fill_ring() where an explicit barrier would be obviously
missing. The latter function however has to make sure that "ringing the
bell" doesn't happen before RX ring entry is really written.

The patch has been successfully tested on Octeon II.

Fixes: a999933db9ed ("MIPS: remove mips_swiotlb_ops")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin &lt;alexander.sverdlin@nokia.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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>
commit 0c34bb598c510e070160029f34efeeb217000f8d upstream.

The removal of mips_swiotlb_ops exposed a problem in octeon_mgmt Ethernet
driver. mips_swiotlb_ops had an mb() after most of the operations and the
removal of the ops had broken the receive functionality of the driver.
My code inspection has shown no other places except
octeon_mgmt_rx_fill_ring() where an explicit barrier would be obviously
missing. The latter function however has to make sure that "ringing the
bell" doesn't happen before RX ring entry is really written.

The patch has been successfully tested on Octeon II.

Fixes: a999933db9ed ("MIPS: remove mips_swiotlb_ops")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin &lt;alexander.sverdlin@nokia.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>e1000e: Do not wake up the system via WOL if device wakeup is disabled</title>
<updated>2020-06-24T15:49:26+00:00</updated>
<author>
<name>Chen Yu</name>
<email>yu.c.chen@intel.com</email>
</author>
<published>2020-05-21T17:59:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ecd872aa3197d189f35fb122a501810924fd80e8'/>
<id>ecd872aa3197d189f35fb122a501810924fd80e8</id>
<content type='text'>
commit 6bf6be1127f7e6d4bf39f84d56854e944d045d74 upstream.

Currently the system will be woken up via WOL(Wake On LAN) even if the
device wakeup ability has been disabled via sysfs:
 cat /sys/devices/pci0000:00/0000:00:1f.6/power/wakeup
 disabled

The system should not be woken up if the user has explicitly
disabled the wake up ability for this device.

This patch clears the WOL ability of this network device if the
user has disabled the wake up ability in sysfs.

Fixes: bc7f75fa9788 ("[E1000E]: New pci-express e1000 driver")
Reported-by: "Rafael J. Wysocki" &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: &lt;Stable@vger.kernel.org&gt;
Signed-off-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Tested-by: Aaron Brown &lt;aaron.f.brown@intel.com&gt;
Signed-off-by: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&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>
commit 6bf6be1127f7e6d4bf39f84d56854e944d045d74 upstream.

Currently the system will be woken up via WOL(Wake On LAN) even if the
device wakeup ability has been disabled via sysfs:
 cat /sys/devices/pci0000:00/0000:00:1f.6/power/wakeup
 disabled

The system should not be woken up if the user has explicitly
disabled the wake up ability for this device.

This patch clears the WOL ability of this network device if the
user has disabled the wake up ability in sysfs.

Fixes: bc7f75fa9788 ("[E1000E]: New pci-express e1000 driver")
Reported-by: "Rafael J. Wysocki" &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: &lt;Stable@vger.kernel.org&gt;
Signed-off-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Tested-by: Aaron Brown &lt;aaron.f.brown@intel.com&gt;
Signed-off-by: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/64s: Fix KVM interrupt using wrong save area</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Nicholas Piggin</name>
<email>npiggin@gmail.com</email>
</author>
<published>2020-06-15T06:12:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9644d65c07e1a80221ec5156fba296f36ed886ad'/>
<id>9644d65c07e1a80221ec5156fba296f36ed886ad</id>
<content type='text'>
commit 0bdcfa182506526fbe4e088ff9ca86a31b81828d upstream.

The CTR register reload in the KVM interrupt path used the wrong save
area for SLB (and NMI) interrupts.

Fixes: 9600f261acaa ("powerpc/64s/exception: Move KVM test to common code")
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Christian Zigotzky &lt;chzigotzky@xenosoft.de&gt;
Signed-off-by: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Tested-by: Christian Zigotzky &lt;chzigotzky@xenosoft.de&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20200615061247.1310763-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0bdcfa182506526fbe4e088ff9ca86a31b81828d upstream.

The CTR register reload in the KVM interrupt path used the wrong save
area for SLB (and NMI) interrupts.

Fixes: 9600f261acaa ("powerpc/64s/exception: Move KVM test to common code")
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Christian Zigotzky &lt;chzigotzky@xenosoft.de&gt;
Signed-off-by: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Tested-by: Christian Zigotzky &lt;chzigotzky@xenosoft.de&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20200615061247.1310763-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>kretprobe: Prevent triggering kretprobe from within kprobe_flush_task</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@redhat.com</email>
</author>
<published>2020-05-12T08:03:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=579d96b83c9eb4418cb29dfa810556fea98e89c3'/>
<id>579d96b83c9eb4418cb29dfa810556fea98e89c3</id>
<content type='text'>
commit 9b38cc704e844e41d9cf74e647bff1d249512cb3 upstream.

Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave.
My test was also able to trigger lockdep output:

 ============================================
 WARNING: possible recursive locking detected
 5.6.0-rc6+ #6 Not tainted
 --------------------------------------------
 sched-messaging/2767 is trying to acquire lock:
 ffffffff9a492798 (&amp;(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0

 but task is already holding lock:
 ffffffff9a491a18 (&amp;(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&amp;(kretprobe_table_locks[i].lock));
   lock(&amp;(kretprobe_table_locks[i].lock));

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 1 lock held by sched-messaging/2767:
  #0: ffffffff9a491a18 (&amp;(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 stack backtrace:
 CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6
 Call Trace:
  dump_stack+0x96/0xe0
  __lock_acquire.cold.57+0x173/0x2b7
  ? native_queued_spin_lock_slowpath+0x42b/0x9e0
  ? lockdep_hardirqs_on+0x590/0x590
  ? __lock_acquire+0xf63/0x4030
  lock_acquire+0x15a/0x3d0
  ? kretprobe_hash_lock+0x52/0xa0
  _raw_spin_lock_irqsave+0x36/0x70
  ? kretprobe_hash_lock+0x52/0xa0
  kretprobe_hash_lock+0x52/0xa0
  trampoline_handler+0xf8/0x940
  ? kprobe_fault_handler+0x380/0x380
  ? find_held_lock+0x3a/0x1c0
  kretprobe_trampoline+0x25/0x50
  ? lock_acquired+0x392/0xbc0
  ? _raw_spin_lock_irqsave+0x50/0x70
  ? __get_valid_kprobe+0x1f0/0x1f0
  ? _raw_spin_unlock_irqrestore+0x3b/0x40
  ? finish_task_switch+0x4b9/0x6d0
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70

The code within the kretprobe handler checks for probe reentrancy,
so we won't trigger any _raw_spin_lock_irqsave probe in there.

The problem is in outside kprobe_flush_task, where we call:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave

where _raw_spin_lock_irqsave triggers the kretprobe and installs
kretprobe_trampoline handler on _raw_spin_lock_irqsave return.

The kretprobe_trampoline handler is then executed with already
locked kretprobe_table_locks, and first thing it does is to
lock kretprobe_table_locks ;-) the whole lockup path like:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave ---&gt; probe triggered, kretprobe_trampoline installed

        ---&gt; kretprobe_table_locks locked

        kretprobe_trampoline
          trampoline_handler
            kretprobe_hash_lock(current, &amp;head, &amp;flags);  &lt;--- deadlock

Adding kprobe_busy_begin/end helpers that mark code with fake
probe installed to prevent triggering of another kprobe within
this code.

Using these helpers in kprobe_flush_task, so the probe recursion
protection check is hit and the probe is never set to prevent
above lockup.

Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2

Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking")
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: "Gustavo A . R . Silva" &lt;gustavoars@kernel.org&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Cc: "Naveen N . Rao" &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Anil S Keshavamurthy &lt;anil.s.keshavamurthy@intel.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: stable@vger.kernel.org
Reported-by: "Ziqian SUN (Zamir)" &lt;zsun@redhat.com&gt;
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.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>
commit 9b38cc704e844e41d9cf74e647bff1d249512cb3 upstream.

Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave.
My test was also able to trigger lockdep output:

 ============================================
 WARNING: possible recursive locking detected
 5.6.0-rc6+ #6 Not tainted
 --------------------------------------------
 sched-messaging/2767 is trying to acquire lock:
 ffffffff9a492798 (&amp;(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0

 but task is already holding lock:
 ffffffff9a491a18 (&amp;(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&amp;(kretprobe_table_locks[i].lock));
   lock(&amp;(kretprobe_table_locks[i].lock));

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 1 lock held by sched-messaging/2767:
  #0: ffffffff9a491a18 (&amp;(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 stack backtrace:
 CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6
 Call Trace:
  dump_stack+0x96/0xe0
  __lock_acquire.cold.57+0x173/0x2b7
  ? native_queued_spin_lock_slowpath+0x42b/0x9e0
  ? lockdep_hardirqs_on+0x590/0x590
  ? __lock_acquire+0xf63/0x4030
  lock_acquire+0x15a/0x3d0
  ? kretprobe_hash_lock+0x52/0xa0
  _raw_spin_lock_irqsave+0x36/0x70
  ? kretprobe_hash_lock+0x52/0xa0
  kretprobe_hash_lock+0x52/0xa0
  trampoline_handler+0xf8/0x940
  ? kprobe_fault_handler+0x380/0x380
  ? find_held_lock+0x3a/0x1c0
  kretprobe_trampoline+0x25/0x50
  ? lock_acquired+0x392/0xbc0
  ? _raw_spin_lock_irqsave+0x50/0x70
  ? __get_valid_kprobe+0x1f0/0x1f0
  ? _raw_spin_unlock_irqrestore+0x3b/0x40
  ? finish_task_switch+0x4b9/0x6d0
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70

The code within the kretprobe handler checks for probe reentrancy,
so we won't trigger any _raw_spin_lock_irqsave probe in there.

The problem is in outside kprobe_flush_task, where we call:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave

where _raw_spin_lock_irqsave triggers the kretprobe and installs
kretprobe_trampoline handler on _raw_spin_lock_irqsave return.

The kretprobe_trampoline handler is then executed with already
locked kretprobe_table_locks, and first thing it does is to
lock kretprobe_table_locks ;-) the whole lockup path like:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave ---&gt; probe triggered, kretprobe_trampoline installed

        ---&gt; kretprobe_table_locks locked

        kretprobe_trampoline
          trampoline_handler
            kretprobe_hash_lock(current, &amp;head, &amp;flags);  &lt;--- deadlock

Adding kprobe_busy_begin/end helpers that mark code with fake
probe installed to prevent triggering of another kprobe within
this code.

Using these helpers in kprobe_flush_task, so the probe recursion
protection check is hit and the probe is never set to prevent
above lockup.

Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2

Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking")
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: "Gustavo A . R . Silva" &lt;gustavoars@kernel.org&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Cc: "Naveen N . Rao" &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Anil S Keshavamurthy &lt;anil.s.keshavamurthy@intel.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: stable@vger.kernel.org
Reported-by: "Ziqian SUN (Zamir)" &lt;zsun@redhat.com&gt;
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Masami Hiramatsu</name>
<email>mhiramat@kernel.org</email>
</author>
<published>2020-05-12T08:02:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=34f07405f9526e2ae8215fc5afcaf633ad5cf2ec'/>
<id>34f07405f9526e2ae8215fc5afcaf633ad5cf2ec</id>
<content type='text'>
commit 1a0aa991a6274161c95a844c58cfb801d681eb59 upstream.

In kprobe_optimizer() kick_kprobe_optimizer() is called
without kprobe_mutex, but this can race with other caller
which is protected by kprobe_mutex.

To fix that, expand kprobe_mutex protected area to protect
kick_kprobe_optimizer() call.

Link: http://lkml.kernel.org/r/158927057586.27680.5036330063955940456.stgit@devnote2

Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing")
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: "Gustavo A . R . Silva" &lt;gustavoars@kernel.org&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Cc: "Naveen N . Rao" &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Anil S Keshavamurthy &lt;anil.s.keshavamurthy@intel.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ziqian SUN &lt;zsun@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.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>
commit 1a0aa991a6274161c95a844c58cfb801d681eb59 upstream.

In kprobe_optimizer() kick_kprobe_optimizer() is called
without kprobe_mutex, but this can race with other caller
which is protected by kprobe_mutex.

To fix that, expand kprobe_mutex protected area to protect
kick_kprobe_optimizer() call.

Link: http://lkml.kernel.org/r/158927057586.27680.5036330063955940456.stgit@devnote2

Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing")
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: "Gustavo A . R . Silva" &lt;gustavoars@kernel.org&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Cc: "Naveen N . Rao" &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Anil S Keshavamurthy &lt;anil.s.keshavamurthy@intel.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ziqian SUN &lt;zsun@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: nft_set_pipapo: Disable preemption before getting per-CPU pointer</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Stefano Brivio</name>
<email>sbrivio@redhat.com</email>
</author>
<published>2020-06-08T08:50:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=54d07919e881ef43225dd5fc2d4ddf5cb3a5a05d'/>
<id>54d07919e881ef43225dd5fc2d4ddf5cb3a5a05d</id>
<content type='text'>
commit c3829285b2e6a0d5461078d7f6cbb2c2b4bf8c4e upstream.

The lkp kernel test robot reports, with CONFIG_DEBUG_PREEMPT enabled:

  [  165.316525] BUG: using smp_processor_id() in preemptible [00000000] code: nft/6247
  [  165.319547] caller is nft_pipapo_insert+0x464/0x610 [nf_tables]
  [  165.321846] CPU: 1 PID: 6247 Comm: nft Not tainted 5.6.0-rc5-01595-ge32a4dc6512ce3 #1
  [  165.332128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
  [  165.334892] Call Trace:
  [  165.336435]  dump_stack+0x8f/0xcb
  [  165.338128]  debug_smp_processor_id+0xb2/0xc0
  [  165.340117]  nft_pipapo_insert+0x464/0x610 [nf_tables]
  [  165.342290]  ? nft_trans_alloc_gfp+0x1c/0x60 [nf_tables]
  [  165.344420]  ? rcu_read_lock_sched_held+0x52/0x80
  [  165.346460]  ? nft_trans_alloc_gfp+0x1c/0x60 [nf_tables]
  [  165.348543]  ? __mmu_interval_notifier_insert+0xa0/0xf0
  [  165.350629]  nft_add_set_elem+0x5ff/0xa90 [nf_tables]
  [  165.352699]  ? __lock_acquire+0x241/0x1400
  [  165.354573]  ? __lock_acquire+0x241/0x1400
  [  165.356399]  ? reacquire_held_locks+0x12f/0x200
  [  165.358384]  ? nf_tables_valid_genid+0x1f/0x40 [nf_tables]
  [  165.360502]  ? nla_strcmp+0x10/0x50
  [  165.362199]  ? nft_table_lookup+0x4f/0xa0 [nf_tables]
  [  165.364217]  ? nla_strcmp+0x10/0x50
  [  165.365891]  ? nf_tables_newsetelem+0xd5/0x150 [nf_tables]
  [  165.367997]  nf_tables_newsetelem+0xd5/0x150 [nf_tables]
  [  165.370083]  nfnetlink_rcv_batch+0x4fd/0x790 [nfnetlink]
  [  165.372205]  ? __lock_acquire+0x241/0x1400
  [  165.374058]  ? __nla_validate_parse+0x57/0x8a0
  [  165.375989]  ? cap_inode_getsecurity+0x230/0x230
  [  165.377954]  ? security_capable+0x38/0x50
  [  165.379795]  nfnetlink_rcv+0x11d/0x140 [nfnetlink]
  [  165.381779]  netlink_unicast+0x1b2/0x280
  [  165.383612]  netlink_sendmsg+0x351/0x470
  [  165.385439]  sock_sendmsg+0x5b/0x60
  [  165.387133]  ____sys_sendmsg+0x200/0x280
  [  165.388871]  ? copy_msghdr_from_user+0xd9/0x160
  [  165.390805]  ___sys_sendmsg+0x88/0xd0
  [  165.392524]  ? __might_fault+0x3e/0x90
  [  165.394273]  ? sock_getsockopt+0x3d5/0xbb0
  [  165.396021]  ? __handle_mm_fault+0x545/0x6a0
  [  165.397822]  ? find_held_lock+0x2d/0x90
  [  165.399593]  ? __sys_sendmsg+0x5e/0xa0
  [  165.401338]  __sys_sendmsg+0x5e/0xa0
  [  165.402979]  do_syscall_64+0x60/0x280
  [  165.404680]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  [  165.406621] RIP: 0033:0x7ff1fa46e783
  [  165.408299] Code: c7 c0 ff ff ff ff eb bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 2e 00 00 00 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 28 89 54 24 1c 48
  [  165.414163] RSP: 002b:00007ffedf59ea78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
  [  165.416804] RAX: ffffffffffffffda RBX: 00007ffedf59fc60 RCX: 00007ff1fa46e783
  [  165.419419] RDX: 0000000000000000 RSI: 00007ffedf59fb10 RDI: 0000000000000005
  [  165.421886] RBP: 00007ffedf59fc10 R08: 00007ffedf59ea54 R09: 0000000000000001
  [  165.424445] R10: 00007ff1fa630c6c R11: 0000000000000246 R12: 0000000000020000
  [  165.426954] R13: 0000000000000280 R14: 0000000000000005 R15: 00007ffedf59ea90

Disable preemption before accessing the lookup scratch area in
nft_pipapo_insert().

Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Analysed-by: Florian Westphal &lt;fw@strlen.de&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.6.x
Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Signed-off-by: Stefano Brivio &lt;sbrivio@redhat.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.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>
commit c3829285b2e6a0d5461078d7f6cbb2c2b4bf8c4e upstream.

The lkp kernel test robot reports, with CONFIG_DEBUG_PREEMPT enabled:

  [  165.316525] BUG: using smp_processor_id() in preemptible [00000000] code: nft/6247
  [  165.319547] caller is nft_pipapo_insert+0x464/0x610 [nf_tables]
  [  165.321846] CPU: 1 PID: 6247 Comm: nft Not tainted 5.6.0-rc5-01595-ge32a4dc6512ce3 #1
  [  165.332128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
  [  165.334892] Call Trace:
  [  165.336435]  dump_stack+0x8f/0xcb
  [  165.338128]  debug_smp_processor_id+0xb2/0xc0
  [  165.340117]  nft_pipapo_insert+0x464/0x610 [nf_tables]
  [  165.342290]  ? nft_trans_alloc_gfp+0x1c/0x60 [nf_tables]
  [  165.344420]  ? rcu_read_lock_sched_held+0x52/0x80
  [  165.346460]  ? nft_trans_alloc_gfp+0x1c/0x60 [nf_tables]
  [  165.348543]  ? __mmu_interval_notifier_insert+0xa0/0xf0
  [  165.350629]  nft_add_set_elem+0x5ff/0xa90 [nf_tables]
  [  165.352699]  ? __lock_acquire+0x241/0x1400
  [  165.354573]  ? __lock_acquire+0x241/0x1400
  [  165.356399]  ? reacquire_held_locks+0x12f/0x200
  [  165.358384]  ? nf_tables_valid_genid+0x1f/0x40 [nf_tables]
  [  165.360502]  ? nla_strcmp+0x10/0x50
  [  165.362199]  ? nft_table_lookup+0x4f/0xa0 [nf_tables]
  [  165.364217]  ? nla_strcmp+0x10/0x50
  [  165.365891]  ? nf_tables_newsetelem+0xd5/0x150 [nf_tables]
  [  165.367997]  nf_tables_newsetelem+0xd5/0x150 [nf_tables]
  [  165.370083]  nfnetlink_rcv_batch+0x4fd/0x790 [nfnetlink]
  [  165.372205]  ? __lock_acquire+0x241/0x1400
  [  165.374058]  ? __nla_validate_parse+0x57/0x8a0
  [  165.375989]  ? cap_inode_getsecurity+0x230/0x230
  [  165.377954]  ? security_capable+0x38/0x50
  [  165.379795]  nfnetlink_rcv+0x11d/0x140 [nfnetlink]
  [  165.381779]  netlink_unicast+0x1b2/0x280
  [  165.383612]  netlink_sendmsg+0x351/0x470
  [  165.385439]  sock_sendmsg+0x5b/0x60
  [  165.387133]  ____sys_sendmsg+0x200/0x280
  [  165.388871]  ? copy_msghdr_from_user+0xd9/0x160
  [  165.390805]  ___sys_sendmsg+0x88/0xd0
  [  165.392524]  ? __might_fault+0x3e/0x90
  [  165.394273]  ? sock_getsockopt+0x3d5/0xbb0
  [  165.396021]  ? __handle_mm_fault+0x545/0x6a0
  [  165.397822]  ? find_held_lock+0x2d/0x90
  [  165.399593]  ? __sys_sendmsg+0x5e/0xa0
  [  165.401338]  __sys_sendmsg+0x5e/0xa0
  [  165.402979]  do_syscall_64+0x60/0x280
  [  165.404680]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  [  165.406621] RIP: 0033:0x7ff1fa46e783
  [  165.408299] Code: c7 c0 ff ff ff ff eb bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 2e 00 00 00 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 28 89 54 24 1c 48
  [  165.414163] RSP: 002b:00007ffedf59ea78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
  [  165.416804] RAX: ffffffffffffffda RBX: 00007ffedf59fc60 RCX: 00007ff1fa46e783
  [  165.419419] RDX: 0000000000000000 RSI: 00007ffedf59fb10 RDI: 0000000000000005
  [  165.421886] RBP: 00007ffedf59fc10 R08: 00007ffedf59ea54 R09: 0000000000000001
  [  165.424445] R10: 00007ff1fa630c6c R11: 0000000000000246 R12: 0000000000020000
  [  165.426954] R13: 0000000000000280 R14: 0000000000000005 R15: 00007ffedf59ea90

Disable preemption before accessing the lookup scratch area in
nft_pipapo_insert().

Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Analysed-by: Florian Westphal &lt;fw@strlen.de&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.6.x
Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Signed-off-by: Stefano Brivio &lt;sbrivio@redhat.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: nft_set_rbtree: Don't account for expired elements on insertion</title>
<updated>2020-06-24T15:49:25+00:00</updated>
<author>
<name>Stefano Brivio</name>
<email>sbrivio@redhat.com</email>
</author>
<published>2020-06-02T23:50:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a317c1f43af53d261e05a98abc99f28474e5069b'/>
<id>a317c1f43af53d261e05a98abc99f28474e5069b</id>
<content type='text'>
commit 33d077996a87175b155fe88030e8fec7ca76327e upstream.

While checking the validity of insertion in __nft_rbtree_insert(),
we currently ignore conflicting elements and intervals only if they
are not active within the next generation.

However, if we consider expired elements and intervals as
potentially conflicting and overlapping, we'll return error for
entries that should be added instead. This is particularly visible
with garbage collection intervals that are comparable with the
element timeout itself, as reported by Mike Dillinger.

Other than the simple issue of denying insertion of valid entries,
this might also result in insertion of a single element (opening or
closing) out of a given interval. With single entries (that are
inserted as intervals of size 1), this leads in turn to the creation
of new intervals. For example:

  # nft add element t s { 192.0.2.1 }
  # nft list ruleset
  [...]
     elements = { 192.0.2.1-255.255.255.255 }

Always ignore expired elements active in the next generation, while
checking for conflicts.

It might be more convenient to introduce a new macro that covers
both inactive and expired items, as this type of check also appears
quite frequently in other set back-ends. This is however beyond the
scope of this fix and can be deferred to a separate patch.

Other than the overlap detection cases introduced by commit
7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps
on insertion"), we also have to cover the original conflict check
dealing with conflicts between two intervals of size 1, which was
introduced before support for timeout was introduced. This won't
return an error to the user as -EEXIST is masked by nft if
NLM_F_EXCL is not given, but would result in a silent failure
adding the entry.

Reported-by: Mike Dillinger &lt;miked@softtalker.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.6.x
Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support")
Fixes: 7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps on insertion")
Signed-off-by: Stefano Brivio &lt;sbrivio@redhat.com&gt;
Acked-by: Phil Sutter &lt;phil@nwl.cc&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.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>
commit 33d077996a87175b155fe88030e8fec7ca76327e upstream.

While checking the validity of insertion in __nft_rbtree_insert(),
we currently ignore conflicting elements and intervals only if they
are not active within the next generation.

However, if we consider expired elements and intervals as
potentially conflicting and overlapping, we'll return error for
entries that should be added instead. This is particularly visible
with garbage collection intervals that are comparable with the
element timeout itself, as reported by Mike Dillinger.

Other than the simple issue of denying insertion of valid entries,
this might also result in insertion of a single element (opening or
closing) out of a given interval. With single entries (that are
inserted as intervals of size 1), this leads in turn to the creation
of new intervals. For example:

  # nft add element t s { 192.0.2.1 }
  # nft list ruleset
  [...]
     elements = { 192.0.2.1-255.255.255.255 }

Always ignore expired elements active in the next generation, while
checking for conflicts.

It might be more convenient to introduce a new macro that covers
both inactive and expired items, as this type of check also appears
quite frequently in other set back-ends. This is however beyond the
scope of this fix and can be deferred to a separate patch.

Other than the overlap detection cases introduced by commit
7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps
on insertion"), we also have to cover the original conflict check
dealing with conflicts between two intervals of size 1, which was
introduced before support for timeout was introduced. This won't
return an error to the user as -EEXIST is masked by nft if
NLM_F_EXCL is not given, but would result in a silent failure
adding the entry.

Reported-by: Mike Dillinger &lt;miked@softtalker.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.6.x
Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support")
Fixes: 7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps on insertion")
Signed-off-by: Stefano Brivio &lt;sbrivio@redhat.com&gt;
Acked-by: Phil Sutter &lt;phil@nwl.cc&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
