<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/kernel, branch v4.0.5</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>sched: always use blk_schedule_flush_plug in io_schedule_out</title>
<updated>2015-06-06T15:21:04+00:00</updated>
<author>
<name>Shaohua Li</name>
<email>shli@fb.com</email>
</author>
<published>2015-05-08T17:51:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=22f546a33bac11aea8af5e570f296234ecdd60d4'/>
<id>22f546a33bac11aea8af5e570f296234ecdd60d4</id>
<content type='text'>
commit 10d784eae2b41e25d8fc6a88096cd27286093c84 upstream.

block plug callback could sleep, so we introduce a parameter
'from_schedule' and corresponding drivers can use it to destinguish a
schedule plug flush or a plug finish. Unfortunately io_schedule_out
still uses blk_flush_plug(). This causes below output (Note, I added a
might_sleep() in raid1_unplug to make it trigger faster, but the whole
thing doesn't matter if I add might_sleep). In raid1/10, this can cause
deadlock.

This patch makes io_schedule_out always uses blk_schedule_flush_plug.
This should only impact drivers (as far as I know, raid 1/10) which are
sensitive to the 'from_schedule' parameter.

[  370.817949] ------------[ cut here ]------------
[  370.817960] WARNING: CPU: 7 PID: 145 at ../kernel/sched/core.c:7306 __might_sleep+0x7f/0x90()
[  370.817969] do not call blocking ops when !TASK_RUNNING; state=2 set at [&lt;ffffffff81092fcf&gt;] prepare_to_wait+0x2f/0x90
[  370.817971] Modules linked in: raid1
[  370.817976] CPU: 7 PID: 145 Comm: kworker/u16:9 Tainted: G        W       4.0.0+ #361
[  370.817977] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153802- 04/01/2014
[  370.817983] Workqueue: writeback bdi_writeback_workfn (flush-9:1)
[  370.817985]  ffffffff81cd83be ffff8800ba8cb298 ffffffff819dd7af 0000000000000001
[  370.817988]  ffff8800ba8cb2e8 ffff8800ba8cb2d8 ffffffff81051afc ffff8800ba8cb2c8
[  370.817990]  ffffffffa00061a8 000000000000041e 0000000000000000 ffff8800ba8cba28
[  370.817993] Call Trace:
[  370.817999]  [&lt;ffffffff819dd7af&gt;] dump_stack+0x4f/0x7b
[  370.818002]  [&lt;ffffffff81051afc&gt;] warn_slowpath_common+0x8c/0xd0
[  370.818004]  [&lt;ffffffff81051b86&gt;] warn_slowpath_fmt+0x46/0x50
[  370.818006]  [&lt;ffffffff81092fcf&gt;] ? prepare_to_wait+0x2f/0x90
[  370.818008]  [&lt;ffffffff81092fcf&gt;] ? prepare_to_wait+0x2f/0x90
[  370.818010]  [&lt;ffffffff810776ef&gt;] __might_sleep+0x7f/0x90
[  370.818014]  [&lt;ffffffffa0000c03&gt;] raid1_unplug+0xd3/0x170 [raid1]
[  370.818024]  [&lt;ffffffff81421d9a&gt;] blk_flush_plug_list+0x8a/0x1e0
[  370.818028]  [&lt;ffffffff819e3550&gt;] ? bit_wait+0x50/0x50
[  370.818031]  [&lt;ffffffff819e21b0&gt;] io_schedule_timeout+0x130/0x140
[  370.818033]  [&lt;ffffffff819e3586&gt;] bit_wait_io+0x36/0x50
[  370.818034]  [&lt;ffffffff819e31b5&gt;] __wait_on_bit+0x65/0x90
[  370.818041]  [&lt;ffffffff8125b67c&gt;] ? ext4_read_block_bitmap_nowait+0xbc/0x630
[  370.818043]  [&lt;ffffffff819e3550&gt;] ? bit_wait+0x50/0x50
[  370.818045]  [&lt;ffffffff819e3302&gt;] out_of_line_wait_on_bit+0x72/0x80
[  370.818047]  [&lt;ffffffff810935e0&gt;] ? autoremove_wake_function+0x40/0x40
[  370.818050]  [&lt;ffffffff811de744&gt;] __wait_on_buffer+0x44/0x50
[  370.818053]  [&lt;ffffffff8125ae80&gt;] ext4_wait_block_bitmap+0xe0/0xf0
[  370.818058]  [&lt;ffffffff812975d6&gt;] ext4_mb_init_cache+0x206/0x790
[  370.818062]  [&lt;ffffffff8114bc6c&gt;] ? lru_cache_add+0x1c/0x50
[  370.818064]  [&lt;ffffffff81297c7e&gt;] ext4_mb_init_group+0x11e/0x200
[  370.818066]  [&lt;ffffffff81298231&gt;] ext4_mb_load_buddy+0x341/0x360
[  370.818068]  [&lt;ffffffff8129a1a3&gt;] ext4_mb_find_by_goal+0x93/0x2f0
[  370.818070]  [&lt;ffffffff81295b54&gt;] ? ext4_mb_normalize_request+0x1e4/0x5b0
[  370.818072]  [&lt;ffffffff8129ab67&gt;] ext4_mb_regular_allocator+0x67/0x460
[  370.818074]  [&lt;ffffffff81295b54&gt;] ? ext4_mb_normalize_request+0x1e4/0x5b0
[  370.818076]  [&lt;ffffffff8129ca4b&gt;] ext4_mb_new_blocks+0x4cb/0x620
[  370.818079]  [&lt;ffffffff81290956&gt;] ext4_ext_map_blocks+0x4c6/0x14d0
[  370.818081]  [&lt;ffffffff812a4d4e&gt;] ? ext4_es_lookup_extent+0x4e/0x290
[  370.818085]  [&lt;ffffffff8126399d&gt;] ext4_map_blocks+0x14d/0x4f0
[  370.818088]  [&lt;ffffffff81266fbd&gt;] ext4_writepages+0x76d/0xe50
[  370.818094]  [&lt;ffffffff81149691&gt;] do_writepages+0x21/0x50
[  370.818097]  [&lt;ffffffff811d5c00&gt;] __writeback_single_inode+0x60/0x490
[  370.818099]  [&lt;ffffffff811d630a&gt;] writeback_sb_inodes+0x2da/0x590
[  370.818103]  [&lt;ffffffff811abf4b&gt;] ? trylock_super+0x1b/0x50
[  370.818105]  [&lt;ffffffff811abf4b&gt;] ? trylock_super+0x1b/0x50
[  370.818107]  [&lt;ffffffff811d665f&gt;] __writeback_inodes_wb+0x9f/0xd0
[  370.818109]  [&lt;ffffffff811d69db&gt;] wb_writeback+0x34b/0x3c0
[  370.818111]  [&lt;ffffffff811d70df&gt;] bdi_writeback_workfn+0x23f/0x550
[  370.818116]  [&lt;ffffffff8106bbd8&gt;] process_one_work+0x1c8/0x570
[  370.818117]  [&lt;ffffffff8106bb5b&gt;] ? process_one_work+0x14b/0x570
[  370.818119]  [&lt;ffffffff8106c09b&gt;] worker_thread+0x11b/0x470
[  370.818121]  [&lt;ffffffff8106bf80&gt;] ? process_one_work+0x570/0x570
[  370.818124]  [&lt;ffffffff81071868&gt;] kthread+0xf8/0x110
[  370.818126]  [&lt;ffffffff81071770&gt;] ? kthread_create_on_node+0x210/0x210
[  370.818129]  [&lt;ffffffff819e9322&gt;] ret_from_fork+0x42/0x70
[  370.818131]  [&lt;ffffffff81071770&gt;] ? kthread_create_on_node+0x210/0x210
[  370.818132] ---[ end trace 7b4deb71e68b6605 ]---

V2: don't change -&gt;in_iowait

Cc: NeilBrown &lt;neilb@suse.de&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
Reviewed-by: Jeff Moyer &lt;jmoyer@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Cc: poma &lt;pomidorabelisima@gmail.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 10d784eae2b41e25d8fc6a88096cd27286093c84 upstream.

block plug callback could sleep, so we introduce a parameter
'from_schedule' and corresponding drivers can use it to destinguish a
schedule plug flush or a plug finish. Unfortunately io_schedule_out
still uses blk_flush_plug(). This causes below output (Note, I added a
might_sleep() in raid1_unplug to make it trigger faster, but the whole
thing doesn't matter if I add might_sleep). In raid1/10, this can cause
deadlock.

This patch makes io_schedule_out always uses blk_schedule_flush_plug.
This should only impact drivers (as far as I know, raid 1/10) which are
sensitive to the 'from_schedule' parameter.

[  370.817949] ------------[ cut here ]------------
[  370.817960] WARNING: CPU: 7 PID: 145 at ../kernel/sched/core.c:7306 __might_sleep+0x7f/0x90()
[  370.817969] do not call blocking ops when !TASK_RUNNING; state=2 set at [&lt;ffffffff81092fcf&gt;] prepare_to_wait+0x2f/0x90
[  370.817971] Modules linked in: raid1
[  370.817976] CPU: 7 PID: 145 Comm: kworker/u16:9 Tainted: G        W       4.0.0+ #361
[  370.817977] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153802- 04/01/2014
[  370.817983] Workqueue: writeback bdi_writeback_workfn (flush-9:1)
[  370.817985]  ffffffff81cd83be ffff8800ba8cb298 ffffffff819dd7af 0000000000000001
[  370.817988]  ffff8800ba8cb2e8 ffff8800ba8cb2d8 ffffffff81051afc ffff8800ba8cb2c8
[  370.817990]  ffffffffa00061a8 000000000000041e 0000000000000000 ffff8800ba8cba28
[  370.817993] Call Trace:
[  370.817999]  [&lt;ffffffff819dd7af&gt;] dump_stack+0x4f/0x7b
[  370.818002]  [&lt;ffffffff81051afc&gt;] warn_slowpath_common+0x8c/0xd0
[  370.818004]  [&lt;ffffffff81051b86&gt;] warn_slowpath_fmt+0x46/0x50
[  370.818006]  [&lt;ffffffff81092fcf&gt;] ? prepare_to_wait+0x2f/0x90
[  370.818008]  [&lt;ffffffff81092fcf&gt;] ? prepare_to_wait+0x2f/0x90
[  370.818010]  [&lt;ffffffff810776ef&gt;] __might_sleep+0x7f/0x90
[  370.818014]  [&lt;ffffffffa0000c03&gt;] raid1_unplug+0xd3/0x170 [raid1]
[  370.818024]  [&lt;ffffffff81421d9a&gt;] blk_flush_plug_list+0x8a/0x1e0
[  370.818028]  [&lt;ffffffff819e3550&gt;] ? bit_wait+0x50/0x50
[  370.818031]  [&lt;ffffffff819e21b0&gt;] io_schedule_timeout+0x130/0x140
[  370.818033]  [&lt;ffffffff819e3586&gt;] bit_wait_io+0x36/0x50
[  370.818034]  [&lt;ffffffff819e31b5&gt;] __wait_on_bit+0x65/0x90
[  370.818041]  [&lt;ffffffff8125b67c&gt;] ? ext4_read_block_bitmap_nowait+0xbc/0x630
[  370.818043]  [&lt;ffffffff819e3550&gt;] ? bit_wait+0x50/0x50
[  370.818045]  [&lt;ffffffff819e3302&gt;] out_of_line_wait_on_bit+0x72/0x80
[  370.818047]  [&lt;ffffffff810935e0&gt;] ? autoremove_wake_function+0x40/0x40
[  370.818050]  [&lt;ffffffff811de744&gt;] __wait_on_buffer+0x44/0x50
[  370.818053]  [&lt;ffffffff8125ae80&gt;] ext4_wait_block_bitmap+0xe0/0xf0
[  370.818058]  [&lt;ffffffff812975d6&gt;] ext4_mb_init_cache+0x206/0x790
[  370.818062]  [&lt;ffffffff8114bc6c&gt;] ? lru_cache_add+0x1c/0x50
[  370.818064]  [&lt;ffffffff81297c7e&gt;] ext4_mb_init_group+0x11e/0x200
[  370.818066]  [&lt;ffffffff81298231&gt;] ext4_mb_load_buddy+0x341/0x360
[  370.818068]  [&lt;ffffffff8129a1a3&gt;] ext4_mb_find_by_goal+0x93/0x2f0
[  370.818070]  [&lt;ffffffff81295b54&gt;] ? ext4_mb_normalize_request+0x1e4/0x5b0
[  370.818072]  [&lt;ffffffff8129ab67&gt;] ext4_mb_regular_allocator+0x67/0x460
[  370.818074]  [&lt;ffffffff81295b54&gt;] ? ext4_mb_normalize_request+0x1e4/0x5b0
[  370.818076]  [&lt;ffffffff8129ca4b&gt;] ext4_mb_new_blocks+0x4cb/0x620
[  370.818079]  [&lt;ffffffff81290956&gt;] ext4_ext_map_blocks+0x4c6/0x14d0
[  370.818081]  [&lt;ffffffff812a4d4e&gt;] ? ext4_es_lookup_extent+0x4e/0x290
[  370.818085]  [&lt;ffffffff8126399d&gt;] ext4_map_blocks+0x14d/0x4f0
[  370.818088]  [&lt;ffffffff81266fbd&gt;] ext4_writepages+0x76d/0xe50
[  370.818094]  [&lt;ffffffff81149691&gt;] do_writepages+0x21/0x50
[  370.818097]  [&lt;ffffffff811d5c00&gt;] __writeback_single_inode+0x60/0x490
[  370.818099]  [&lt;ffffffff811d630a&gt;] writeback_sb_inodes+0x2da/0x590
[  370.818103]  [&lt;ffffffff811abf4b&gt;] ? trylock_super+0x1b/0x50
[  370.818105]  [&lt;ffffffff811abf4b&gt;] ? trylock_super+0x1b/0x50
[  370.818107]  [&lt;ffffffff811d665f&gt;] __writeback_inodes_wb+0x9f/0xd0
[  370.818109]  [&lt;ffffffff811d69db&gt;] wb_writeback+0x34b/0x3c0
[  370.818111]  [&lt;ffffffff811d70df&gt;] bdi_writeback_workfn+0x23f/0x550
[  370.818116]  [&lt;ffffffff8106bbd8&gt;] process_one_work+0x1c8/0x570
[  370.818117]  [&lt;ffffffff8106bb5b&gt;] ? process_one_work+0x14b/0x570
[  370.818119]  [&lt;ffffffff8106c09b&gt;] worker_thread+0x11b/0x470
[  370.818121]  [&lt;ffffffff8106bf80&gt;] ? process_one_work+0x570/0x570
[  370.818124]  [&lt;ffffffff81071868&gt;] kthread+0xf8/0x110
[  370.818126]  [&lt;ffffffff81071770&gt;] ? kthread_create_on_node+0x210/0x210
[  370.818129]  [&lt;ffffffff819e9322&gt;] ret_from_fork+0x42/0x70
[  370.818131]  [&lt;ffffffff81071770&gt;] ? kthread_create_on_node+0x210/0x210
[  370.818132] ---[ end trace 7b4deb71e68b6605 ]---

V2: don't change -&gt;in_iowait

Cc: NeilBrown &lt;neilb@suse.de&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
Reviewed-by: Jeff Moyer &lt;jmoyer@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
Cc: poma &lt;pomidorabelisima@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>sched: Handle priority boosted tasks proper in setscheduler()</title>
<updated>2015-06-06T15:21:04+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2015-05-05T17:49:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=31f17ffdaa4265f352810c4ed5d1dc38226191e7'/>
<id>31f17ffdaa4265f352810c4ed5d1dc38226191e7</id>
<content type='text'>
commit 0782e63bc6fe7e2d3408d250df11d388b7799c6b upstream.

Ronny reported that the following scenario is not handled correctly:

	T1 (prio = 10)
	   lock(rtmutex);

	T2 (prio = 20)
	   lock(rtmutex)
	      boost T1

	T1 (prio = 20)
	   sys_set_scheduler(prio = 30)
	   T1 prio = 30
	   ....
	   sys_set_scheduler(prio = 10)
	   T1 prio = 30

The last step is wrong as T1 should now be back at prio 20.

Commit c365c292d059 ("sched: Consider pi boosting in setscheduler()")
only handles the case where a boosted tasks tries to lower its
priority.

Fix it by taking the new effective priority into account for the
decision whether a change of the priority is required.

Reported-by: Ronny Meeus &lt;ronny.meeus@gmail.com&gt;
Tested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Mike Galbraith &lt;umgwanakikbuti@gmail.com&gt;
Fixes: c365c292d059 ("sched: Consider pi boosting in setscheduler()")
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1505051806060.4225@nanos
Signed-off-by: Ingo Molnar &lt;mingo@kernel.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 0782e63bc6fe7e2d3408d250df11d388b7799c6b upstream.

Ronny reported that the following scenario is not handled correctly:

	T1 (prio = 10)
	   lock(rtmutex);

	T2 (prio = 20)
	   lock(rtmutex)
	      boost T1

	T1 (prio = 20)
	   sys_set_scheduler(prio = 30)
	   T1 prio = 30
	   ....
	   sys_set_scheduler(prio = 10)
	   T1 prio = 30

The last step is wrong as T1 should now be back at prio 20.

Commit c365c292d059 ("sched: Consider pi boosting in setscheduler()")
only handles the case where a boosted tasks tries to lower its
priority.

Fix it by taking the new effective priority into account for the
decision whether a change of the priority is required.

Reported-by: Ronny Meeus &lt;ronny.meeus@gmail.com&gt;
Tested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Mike Galbraith &lt;umgwanakikbuti@gmail.com&gt;
Fixes: c365c292d059 ("sched: Consider pi boosting in setscheduler()")
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1505051806060.4225@nanos
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>module: Call module notifier on failure after complete_formation()</title>
<updated>2015-06-06T15:20:57+00:00</updated>
<author>
<name>Steven Rostedt</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2015-05-08T17:36:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=acc27112293c72a1bc249e2913f52a2c0e078fd0'/>
<id>acc27112293c72a1bc249e2913f52a2c0e078fd0</id>
<content type='text'>
commit 37815bf866ab6722a47550f8d25ad3f1a16a680c upstream.

The module notifier call chain for MODULE_STATE_COMING was moved up before
the parsing of args, into the complete_formation() call. But if the module failed
to load after that, the notifier call chain for MODULE_STATE_GOING was
never called and that prevented the users of those call chains from
cleaning up anything that was allocated.

Link: http://lkml.kernel.org/r/554C52B9.9060700@gmail.com

Reported-by: Pontus Fuchs &lt;pontus.fuchs@gmail.com&gt;
Fixes: 4982223e51e8 "module: set nx before marking module MODULE_STATE_COMING"
Signed-off-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Rusty Russell &lt;rusty@rustcorp.com.au&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 37815bf866ab6722a47550f8d25ad3f1a16a680c upstream.

The module notifier call chain for MODULE_STATE_COMING was moved up before
the parsing of args, into the complete_formation() call. But if the module failed
to load after that, the notifier call chain for MODULE_STATE_GOING was
never called and that prevented the users of those call chains from
cleaning up anything that was allocated.

Link: http://lkml.kernel.org/r/554C52B9.9060700@gmail.com

Reported-by: Pontus Fuchs &lt;pontus.fuchs@gmail.com&gt;
Fixes: 4982223e51e8 "module: set nx before marking module MODULE_STATE_COMING"
Signed-off-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Rusty Russell &lt;rusty@rustcorp.com.au&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ktime: Fix ktime_divns to do signed division</title>
<updated>2015-06-06T15:20:49+00:00</updated>
<author>
<name>John Stultz</name>
<email>john.stultz@linaro.org</email>
</author>
<published>2015-05-08T20:47:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1d280829188e2a0f10fbc530dfb7c2fcb2d97acc'/>
<id>1d280829188e2a0f10fbc530dfb7c2fcb2d97acc</id>
<content type='text'>
commit f7bcb70ebae0dcdb5a2d859b09e4465784d99029 upstream.

It was noted that the 32bit implementation of ktime_divns()
was doing unsigned division and didn't properly handle
negative values.

And when a ktime helper was changed to utilize
ktime_divns, it caused a regression on some IR blasters.
See the following bugzilla for details:
  https://bugzilla.redhat.com/show_bug.cgi?id=1200353

This patch fixes the problem in ktime_divns by checking
and preserving the sign bit, and then reapplying it if
appropriate after the division, it also changes the return
type to a s64 to make it more obvious this is expected.

Nicolas also pointed out that negative dividers would
cause infinite loops on 32bit systems, negative dividers
is unlikely for users of this function, but out of caution
this patch adds checks for negative dividers for both
32-bit (BUG_ON) and 64-bit(WARN_ON) versions to make sure
no such use cases creep in.

[ tglx: Hand an u64 to do_div() to avoid the compiler warning ]

Fixes: 166afb64511e 'ktime: Sanitize ktime_to_us/ms conversion'
Reported-and-tested-by: Trevor Cordes &lt;trevor@tecnopolis.ca&gt;
Signed-off-by: John Stultz &lt;john.stultz@linaro.org&gt;
Acked-by: Nicolas Pitre &lt;nicolas.pitre@linaro.org&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Josh Boyer &lt;jwboyer@redhat.com&gt;
Cc: One Thousand Gnomes &lt;gnomes@lxorguk.ukuu.org.uk&gt;
Link: http://lkml.kernel.org/r/1431118043-23452-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&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 f7bcb70ebae0dcdb5a2d859b09e4465784d99029 upstream.

It was noted that the 32bit implementation of ktime_divns()
was doing unsigned division and didn't properly handle
negative values.

And when a ktime helper was changed to utilize
ktime_divns, it caused a regression on some IR blasters.
See the following bugzilla for details:
  https://bugzilla.redhat.com/show_bug.cgi?id=1200353

This patch fixes the problem in ktime_divns by checking
and preserving the sign bit, and then reapplying it if
appropriate after the division, it also changes the return
type to a s64 to make it more obvious this is expected.

Nicolas also pointed out that negative dividers would
cause infinite loops on 32bit systems, negative dividers
is unlikely for users of this function, but out of caution
this patch adds checks for negative dividers for both
32-bit (BUG_ON) and 64-bit(WARN_ON) versions to make sure
no such use cases creep in.

[ tglx: Hand an u64 to do_div() to avoid the compiler warning ]

Fixes: 166afb64511e 'ktime: Sanitize ktime_to_us/ms conversion'
Reported-and-tested-by: Trevor Cordes &lt;trevor@tecnopolis.ca&gt;
Signed-off-by: John Stultz &lt;john.stultz@linaro.org&gt;
Acked-by: Nicolas Pitre &lt;nicolas.pitre@linaro.org&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Josh Boyer &lt;jwboyer@redhat.com&gt;
Cc: One Thousand Gnomes &lt;gnomes@lxorguk.ukuu.org.uk&gt;
Link: http://lkml.kernel.org/r/1431118043-23452-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: fix 64-bit divide</title>
<updated>2015-05-13T12:14:16+00:00</updated>
<author>
<name>Alexei Starovoitov</name>
<email>ast@plumgrid.com</email>
</author>
<published>2015-04-27T21:40:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=59506497a7c844e81254c0a4bc2920510fac9a52'/>
<id>59506497a7c844e81254c0a4bc2920510fac9a52</id>
<content type='text'>
[ Upstream commit 876a7ae65b86d8cec8efe7d15d050ac61116874e ]

ALU64_DIV instruction should be dividing 64-bit by 64-bit,
whereas do_div() does 64-bit by 32-bit divide.
x64 and arm64 JITs correctly implement 64 by 64 unsigned divide.
llvm BPF backend emits code assuming that ALU64_DIV does 64 by 64.

Fixes: 89aa075832b0 ("net: sock: allow eBPF programs to be attached to sockets")
Reported-by: Michael Holzheu &lt;holzheu@linux.vnet.ibm.com&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@plumgrid.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>
[ Upstream commit 876a7ae65b86d8cec8efe7d15d050ac61116874e ]

ALU64_DIV instruction should be dividing 64-bit by 64-bit,
whereas do_div() does 64-bit by 32-bit divide.
x64 and arm64 JITs correctly implement 64 by 64 unsigned divide.
llvm BPF backend emits code assuming that ALU64_DIV does 64 by 64.

Fixes: 89aa075832b0 ("net: sock: allow eBPF programs to be attached to sockets")
Reported-by: Michael Holzheu &lt;holzheu@linux.vnet.ibm.com&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@plumgrid.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>ebpf: verifier: check that call reg with ARG_ANYTHING is initialized</title>
<updated>2015-05-06T20:04:07+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2015-03-12T16:21:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e86ecd8a7bbc590987b4046c523d8caaef8f8b5f'/>
<id>e86ecd8a7bbc590987b4046c523d8caaef8f8b5f</id>
<content type='text'>
commit 80f1d68ccba70b1060c9c7360ca83da430f66bed upstream.

I noticed that a helper function with argument type ARG_ANYTHING does
not need to have an initialized value (register).

This can worst case lead to unintented stack memory leakage in future
helper functions if they are not carefully designed, or unintended
application behaviour in case the application developer was not careful
enough to match a correct helper function signature in the API.

The underlying issue is that ARG_ANYTHING should actually be split
into two different semantics:

  1) ARG_DONTCARE for function arguments that the helper function
     does not care about (in other words: the default for unused
     function arguments), and

  2) ARG_ANYTHING that is an argument actually being used by a
     helper function and *guaranteed* to be an initialized register.

The current risk is low: ARG_ANYTHING is only used for the 'flags'
argument (r4) in bpf_map_update_elem() that internally does strict
checking.

Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Alexei Starovoitov &lt;ast@plumgrid.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 80f1d68ccba70b1060c9c7360ca83da430f66bed upstream.

I noticed that a helper function with argument type ARG_ANYTHING does
not need to have an initialized value (register).

This can worst case lead to unintented stack memory leakage in future
helper functions if they are not carefully designed, or unintended
application behaviour in case the application developer was not careful
enough to match a correct helper function signature in the API.

The underlying issue is that ARG_ANYTHING should actually be split
into two different semantics:

  1) ARG_DONTCARE for function arguments that the helper function
     does not care about (in other words: the default for unused
     function arguments), and

  2) ARG_ANYTHING that is an argument actually being used by a
     helper function and *guaranteed* to be an initialized register.

The current risk is low: ARG_ANYTHING is only used for the 'flags'
argument (r4) in bpf_map_update_elem() that internally does strict
checking.

Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Alexei Starovoitov &lt;ast@plumgrid.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>sched/deadline: Always enqueue on previous rq when dl_task_timer() fires</title>
<updated>2015-05-06T20:04:06+00:00</updated>
<author>
<name>Juri Lelli</name>
<email>juri.lelli@arm.com</email>
</author>
<published>2015-03-31T08:53:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a0e97e698901d058b984bcf1c13693f7a33375b3'/>
<id>a0e97e698901d058b984bcf1c13693f7a33375b3</id>
<content type='text'>
commit 4cd57f97135840f637431c92380c8da3edbe44ed upstream.

dl_task_timer() may fire on a different rq from where a task was removed
after throttling. Since the call path is:

  dl_task_timer() -&gt;
    enqueue_task_dl() -&gt;
      enqueue_dl_entity() -&gt;
        replenish_dl_entity()

and replenish_dl_entity() uses dl_se's rq, we can't use current's rq
in dl_task_timer(), but we need to lock the task's previous one.

Tested-by: Wanpeng Li &lt;wanpeng.li@linux.intel.com&gt;
Signed-off-by: Juri Lelli &lt;juri.lelli@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Kirill Tkhai &lt;ktkhai@parallels.com&gt;
Cc: Juri Lelli &lt;juri.lelli@gmail.com&gt;
Fixes: 3960c8c0c789 ("sched: Make dl_task_time() use task_rq_lock()")
Link: http://lkml.kernel.org/r/1427792017-7356-1-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.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 4cd57f97135840f637431c92380c8da3edbe44ed upstream.

dl_task_timer() may fire on a different rq from where a task was removed
after throttling. Since the call path is:

  dl_task_timer() -&gt;
    enqueue_task_dl() -&gt;
      enqueue_dl_entity() -&gt;
        replenish_dl_entity()

and replenish_dl_entity() uses dl_se's rq, we can't use current's rq
in dl_task_timer(), but we need to lock the task's previous one.

Tested-by: Wanpeng Li &lt;wanpeng.li@linux.intel.com&gt;
Signed-off-by: Juri Lelli &lt;juri.lelli@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Kirill Tkhai &lt;ktkhai@parallels.com&gt;
Cc: Juri Lelli &lt;juri.lelli@gmail.com&gt;
Fixes: 3960c8c0c789 ("sched: Make dl_task_time() use task_rq_lock()")
Link: http://lkml.kernel.org/r/1427792017-7356-1-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Fix incorrect enabling of trace events by boot cmdline</title>
<updated>2015-05-06T20:04:02+00:00</updated>
<author>
<name>Joonsoo Kim</name>
<email>iamjoonsoo.kim@lge.com</email>
</author>
<published>2015-04-16T04:44:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=aaeb6f4d936e550fef1f068d2e883a23f757d5f5'/>
<id>aaeb6f4d936e550fef1f068d2e883a23f757d5f5</id>
<content type='text'>
commit 84fce9db4d7eaebd6cb2ee30c15da6d4e4daf846 upstream.

There is a problem that trace events are not properly enabled with
boot cmdline. The problem is that if we pass "trace_event=kmem:mm_page_alloc"
to the boot cmdline, it enables all kmem trace events, and not just
the page_alloc event.

This is caused by the parsing mechanism. When we parse the cmdline, the buffer
contents is modified due to tokenization. And, if we use this buffer
again, we will get the wrong result.

Unfortunately, this buffer is be accessed three times to set trace events
properly at boot time. So, we need to handle this situation.

There is already code handling ",", but we need another for ":".
This patch adds it.

Link: http://lkml.kernel.org/r/1429159484-22977-1-git-send-email-iamjoonsoo.kim@lge.com

Signed-off-by: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
[ added missing return ret; ]
Signed-off-by: Steven Rostedt &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 84fce9db4d7eaebd6cb2ee30c15da6d4e4daf846 upstream.

There is a problem that trace events are not properly enabled with
boot cmdline. The problem is that if we pass "trace_event=kmem:mm_page_alloc"
to the boot cmdline, it enables all kmem trace events, and not just
the page_alloc event.

This is caused by the parsing mechanism. When we parse the cmdline, the buffer
contents is modified due to tokenization. And, if we use this buffer
again, we will get the wrong result.

Unfortunately, this buffer is be accessed three times to set trace events
properly at boot time. So, we need to handle this situation.

There is already code handling ",", but we need another for ":".
This patch adds it.

Link: http://lkml.kernel.org/r/1429159484-22977-1-git-send-email-iamjoonsoo.kim@lge.com

Signed-off-by: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
[ added missing return ret; ]
Signed-off-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Handle ftrace_dump() atomic context in graph_trace_open()</title>
<updated>2015-05-06T20:04:02+00:00</updated>
<author>
<name>Rabin Vincent</name>
<email>rabin@rab.in</email>
</author>
<published>2015-04-13T20:30:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c62b024af945d20e01c3e8c416b9e00d137e6f02'/>
<id>c62b024af945d20e01c3e8c416b9e00d137e6f02</id>
<content type='text'>
commit ef99b88b16bee753fa51207abdc58ae660453ec6 upstream.

graph_trace_open() can be called in atomic context from ftrace_dump().
Use GFP_ATOMIC for the memory allocations when that's the case, in order
to avoid the following splat.

 BUG: sleeping function called from invalid context at mm/slab.c:2849
 in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/0
 Backtrace:
 ..
 [&lt;8004dc94&gt;] (__might_sleep) from [&lt;801371f4&gt;] (kmem_cache_alloc_trace+0x160/0x238)
  r7:87800040 r6:000080d0 r5:810d16e8 r4:000080d0
 [&lt;80137094&gt;] (kmem_cache_alloc_trace) from [&lt;800cbd60&gt;] (graph_trace_open+0x30/0xd0)
  r10:00000100 r9:809171a8 r8:00008e28 r7:810d16f0 r6:00000001 r5:810d16e8
  r4:810d16f0
 [&lt;800cbd30&gt;] (graph_trace_open) from [&lt;800c79c4&gt;] (trace_init_global_iter+0x50/0x9c)
  r8:00008e28 r7:808c853c r6:00000001 r5:810d16e8 r4:810d16f0 r3:800cbd30
 [&lt;800c7974&gt;] (trace_init_global_iter) from [&lt;800c7aa0&gt;] (ftrace_dump+0x90/0x2ec)
  r4:810d2580 r3:00000000
 [&lt;800c7a10&gt;] (ftrace_dump) from [&lt;80414b2c&gt;] (sysrq_ftrace_dump+0x1c/0x20)
  r10:00000100 r9:809171a8 r8:808f6e7c r7:00000001 r6:00000007 r5:0000007a
  r4:808d5394
 [&lt;80414b10&gt;] (sysrq_ftrace_dump) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
 [&lt;80415498&gt;] (__handle_sysrq) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
  r8:808c8100 r7:808c8444 r6:00000101 r5:00000010 r4:84eb3210
 [&lt;80415668&gt;] (handle_sysrq) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
 [&lt;8042a760&gt;] (pl011_int) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
  r10:809171bc r9:809171a8 r8:00000001 r7:00000026 r6:808c6000 r5:84f01e60
  r4:8454fe00
 [&lt;8007782c&gt;] (handle_irq_event_percpu) from [&lt;80077b44&gt;] (handle_irq_event+0x4c/0x6c)
  r10:808c7ef0 r9:87283e00 r8:00000001 r7:00000000 r6:8454fe00 r5:84f01e60
  r4:84f01e00
 [&lt;80077af8&gt;] (handle_irq_event) from [&lt;8007aa28&gt;] (handle_fasteoi_irq+0xf0/0x1ac)
  r6:808f52a4 r5:84f01e60 r4:84f01e00 r3:00000000
 [&lt;8007a938&gt;] (handle_fasteoi_irq) from [&lt;80076dc0&gt;] (generic_handle_irq+0x3c/0x4c)
  r6:00000026 r5:00000000 r4:00000026 r3:8007a938
 [&lt;80076d84&gt;] (generic_handle_irq) from [&lt;80077128&gt;] (__handle_domain_irq+0x8c/0xfc)
  r4:808c1e38 r3:0000002e
 [&lt;8007709c&gt;] (__handle_domain_irq) from [&lt;800087b8&gt;] (gic_handle_irq+0x34/0x6c)
  r10:80917748 r9:00000001 r8:88802100 r7:808c7ef0 r6:808c8fb0 r5:00000015
  r4:8880210c r3:808c7ef0
 [&lt;80008784&gt;] (gic_handle_irq) from [&lt;80014044&gt;] (__irq_svc+0x44/0x7c)

Link: http://lkml.kernel.org/r/1428953721-31349-1-git-send-email-rabin@rab.in
Link: http://lkml.kernel.org/r/1428957012-2319-1-git-send-email-rabin@rab.in

Signed-off-by: Rabin Vincent &lt;rabin@rab.in&gt;
Signed-off-by: Steven Rostedt &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 ef99b88b16bee753fa51207abdc58ae660453ec6 upstream.

graph_trace_open() can be called in atomic context from ftrace_dump().
Use GFP_ATOMIC for the memory allocations when that's the case, in order
to avoid the following splat.

 BUG: sleeping function called from invalid context at mm/slab.c:2849
 in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/0
 Backtrace:
 ..
 [&lt;8004dc94&gt;] (__might_sleep) from [&lt;801371f4&gt;] (kmem_cache_alloc_trace+0x160/0x238)
  r7:87800040 r6:000080d0 r5:810d16e8 r4:000080d0
 [&lt;80137094&gt;] (kmem_cache_alloc_trace) from [&lt;800cbd60&gt;] (graph_trace_open+0x30/0xd0)
  r10:00000100 r9:809171a8 r8:00008e28 r7:810d16f0 r6:00000001 r5:810d16e8
  r4:810d16f0
 [&lt;800cbd30&gt;] (graph_trace_open) from [&lt;800c79c4&gt;] (trace_init_global_iter+0x50/0x9c)
  r8:00008e28 r7:808c853c r6:00000001 r5:810d16e8 r4:810d16f0 r3:800cbd30
 [&lt;800c7974&gt;] (trace_init_global_iter) from [&lt;800c7aa0&gt;] (ftrace_dump+0x90/0x2ec)
  r4:810d2580 r3:00000000
 [&lt;800c7a10&gt;] (ftrace_dump) from [&lt;80414b2c&gt;] (sysrq_ftrace_dump+0x1c/0x20)
  r10:00000100 r9:809171a8 r8:808f6e7c r7:00000001 r6:00000007 r5:0000007a
  r4:808d5394
 [&lt;80414b10&gt;] (sysrq_ftrace_dump) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
 [&lt;80415498&gt;] (__handle_sysrq) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
  r8:808c8100 r7:808c8444 r6:00000101 r5:00000010 r4:84eb3210
 [&lt;80415668&gt;] (handle_sysrq) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
 [&lt;8042a760&gt;] (pl011_int) from [&lt;800169b8&gt;] (return_to_handler+0x0/0x18)
  r10:809171bc r9:809171a8 r8:00000001 r7:00000026 r6:808c6000 r5:84f01e60
  r4:8454fe00
 [&lt;8007782c&gt;] (handle_irq_event_percpu) from [&lt;80077b44&gt;] (handle_irq_event+0x4c/0x6c)
  r10:808c7ef0 r9:87283e00 r8:00000001 r7:00000000 r6:8454fe00 r5:84f01e60
  r4:84f01e00
 [&lt;80077af8&gt;] (handle_irq_event) from [&lt;8007aa28&gt;] (handle_fasteoi_irq+0xf0/0x1ac)
  r6:808f52a4 r5:84f01e60 r4:84f01e00 r3:00000000
 [&lt;8007a938&gt;] (handle_fasteoi_irq) from [&lt;80076dc0&gt;] (generic_handle_irq+0x3c/0x4c)
  r6:00000026 r5:00000000 r4:00000026 r3:8007a938
 [&lt;80076d84&gt;] (generic_handle_irq) from [&lt;80077128&gt;] (__handle_domain_irq+0x8c/0xfc)
  r4:808c1e38 r3:0000002e
 [&lt;8007709c&gt;] (__handle_domain_irq) from [&lt;800087b8&gt;] (gic_handle_irq+0x34/0x6c)
  r10:80917748 r9:00000001 r8:88802100 r7:808c7ef0 r6:808c8fb0 r5:00000015
  r4:8880210c r3:808c7ef0
 [&lt;80008784&gt;] (gic_handle_irq) from [&lt;80014044&gt;] (__irq_svc+0x44/0x7c)

Link: http://lkml.kernel.org/r/1428953721-31349-1-git-send-email-rabin@rab.in
Link: http://lkml.kernel.org/r/1428957012-2319-1-git-send-email-rabin@rab.in

Signed-off-by: Rabin Vincent &lt;rabin@rab.in&gt;
Signed-off-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ptrace: fix race between ptrace_resume() and wait_task_stopped()</title>
<updated>2015-05-06T20:03:49+00:00</updated>
<author>
<name>Oleg Nesterov</name>
<email>oleg@redhat.com</email>
</author>
<published>2015-04-16T19:47:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=12ea13bf83f15c5cf59b4039295f98b0d7a83881'/>
<id>12ea13bf83f15c5cf59b4039295f98b0d7a83881</id>
<content type='text'>
commit b72c186999e689cb0b055ab1c7b3cd8fffbeb5ed upstream.

ptrace_resume() is called when the tracee is still __TASK_TRACED.  We set
tracee-&gt;exit_code and then wake_up_state() changes tracee-&gt;state.  If the
tracer's sub-thread does wait() in between, task_stopped_code(ptrace =&gt; T)
wrongly looks like another report from tracee.

This confuses debugger, and since wait_task_stopped() clears -&gt;exit_code
the tracee can miss a signal.

Test-case:

	#include &lt;stdio.h&gt;
	#include &lt;unistd.h&gt;
	#include &lt;sys/wait.h&gt;
	#include &lt;sys/ptrace.h&gt;
	#include &lt;pthread.h&gt;
	#include &lt;assert.h&gt;

	int pid;

	void *waiter(void *arg)
	{
		int stat;

		for (;;) {
			assert(pid == wait(&amp;stat));
			assert(WIFSTOPPED(stat));
			if (WSTOPSIG(stat) == SIGHUP)
				continue;

			assert(WSTOPSIG(stat) == SIGCONT);
			printf("ERR! extra/wrong report:%x\n", stat);
		}
	}

	int main(void)
	{
		pthread_t thread;

		pid = fork();
		if (!pid) {
			assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0);
			for (;;)
				kill(getpid(), SIGHUP);
		}

		assert(pthread_create(&amp;thread, NULL, waiter, NULL) == 0);

		for (;;)
			ptrace(PTRACE_CONT, pid, 0, SIGCONT);

		return 0;
	}

Note for stable: the bug is very old, but without 9899d11f6544 "ptrace:
ensure arch_ptrace/ptrace_request can never race with SIGKILL" the fix
should use lock_task_sighand(child).

Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Reported-by: Pavel Labath &lt;labath@google.com&gt;
Tested-by: Pavel Labath &lt;labath@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@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>
commit b72c186999e689cb0b055ab1c7b3cd8fffbeb5ed upstream.

ptrace_resume() is called when the tracee is still __TASK_TRACED.  We set
tracee-&gt;exit_code and then wake_up_state() changes tracee-&gt;state.  If the
tracer's sub-thread does wait() in between, task_stopped_code(ptrace =&gt; T)
wrongly looks like another report from tracee.

This confuses debugger, and since wait_task_stopped() clears -&gt;exit_code
the tracee can miss a signal.

Test-case:

	#include &lt;stdio.h&gt;
	#include &lt;unistd.h&gt;
	#include &lt;sys/wait.h&gt;
	#include &lt;sys/ptrace.h&gt;
	#include &lt;pthread.h&gt;
	#include &lt;assert.h&gt;

	int pid;

	void *waiter(void *arg)
	{
		int stat;

		for (;;) {
			assert(pid == wait(&amp;stat));
			assert(WIFSTOPPED(stat));
			if (WSTOPSIG(stat) == SIGHUP)
				continue;

			assert(WSTOPSIG(stat) == SIGCONT);
			printf("ERR! extra/wrong report:%x\n", stat);
		}
	}

	int main(void)
	{
		pthread_t thread;

		pid = fork();
		if (!pid) {
			assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0);
			for (;;)
				kill(getpid(), SIGHUP);
		}

		assert(pthread_create(&amp;thread, NULL, waiter, NULL) == 0);

		for (;;)
			ptrace(PTRACE_CONT, pid, 0, SIGCONT);

		return 0;
	}

Note for stable: the bug is very old, but without 9899d11f6544 "ptrace:
ensure arch_ptrace/ptrace_request can never race with SIGKILL" the fix
should use lock_task_sighand(child).

Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Reported-by: Pavel Labath &lt;labath@google.com&gt;
Tested-by: Pavel Labath &lt;labath@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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