<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git, branch v4.14.89</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v4.14.89</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v4.14.89'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2018-12-17T08:28:56+00:00</updated>
<entry>
<title>Linux 4.14.89</title>
<updated>2018-12-17T08:28:56+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2018-12-17T08:28:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3beeb2615681fe87f4e6291ade669d50c27ce59a'/>
<id>urn:sha1:3beeb2615681fe87f4e6291ade669d50c27ce59a</id>
<content type='text'>
</content>
</entry>
<entry>
<title>tcp: lack of available data can also cause TSO defer</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2018-12-06T17:58:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4465b31b75490c038777cfccfbdf2ba8e9e5286a'/>
<id>urn:sha1:4465b31b75490c038777cfccfbdf2ba8e9e5286a</id>
<content type='text'>
commit f9bfe4e6a9d08d405fe7b081ee9a13e649c97ecf upstream.

tcp_tso_should_defer() can return true in three different cases :

 1) We are cwnd-limited
 2) We are rwnd-limited
 3) We are application limited.

Neal pointed out that my recent fix went too far, since
it assumed that if we were not in 1) case, we must be rwnd-limited

Fix this by properly populating the is_cwnd_limited and
is_rwnd_limited booleans.

After this change, we can finally move the silly check for FIN
flag only for the application-limited case.

The same move for EOR bit will be handled in net-next,
since commit 1c09f7d073b1 ("tcp: do not try to defer skbs
with eor mark (MSG_EOR)") is scheduled for linux-4.21

Tested by running 200 concurrent netperf -t TCP_RR -- -r 60000,100
and checking none of them was rwnd_limited in the chrono_stat
output from "ss -ti" command.

Fixes: 41727549de3e ("tcp: Do not underestimate rwnd_limited")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Suggested-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Reviewed-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Soheil Hassas Yeganeh &lt;soheil@google.com&gt;
Reviewed-by: Yuchung Cheng &lt;ycheng@google.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>
</entry>
<entry>
<title>IB/hfi1: Fix an out-of-bounds access in get_hw_stats</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Piotr Stankiewicz</name>
<email>piotr.stankiewicz@intel.com</email>
</author>
<published>2018-11-28T14:44:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=01a166012cd16b9ce147744c514f228df6cf495e'/>
<id>urn:sha1:01a166012cd16b9ce147744c514f228df6cf495e</id>
<content type='text'>
commit 36d842194a57f1b21fbc6a6875f2fa2f9a7f8679 upstream.

When running with KASAN, the following trace is produced:

[   62.535888]

==================================================================
[   62.544930] BUG: KASAN: slab-out-of-bounds in
gut_hw_stats+0x122/0x230 [hfi1]
[   62.553856] Write of size 8 at addr ffff88080e8d6330 by task
kworker/0:1/14

[   62.565333] CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted
4.19.0-test-build-kasan+ #8
[   62.575087] Hardware name: Intel Corporation S2600KPR/S2600KPR, BIOS
SE5C610.86B.01.01.0019.101220160604 10/12/2016
[   62.587951] Workqueue: events work_for_cpu_fn
[   62.594050] Call Trace:
[   62.598023]  dump_stack+0xc6/0x14c
[   62.603089]  ? dump_stack_print_info.cold.1+0x2f/0x2f
[   62.610041]  ? kmsg_dump_rewind_nolock+0x59/0x59
[   62.616615]  ? get_hw_stats+0x122/0x230 [hfi1]
[   62.622985]  print_address_description+0x6c/0x23c
[   62.629744]  ? get_hw_stats+0x122/0x230 [hfi1]
[   62.636108]  kasan_report.cold.6+0x241/0x308
[   62.642365]  get_hw_stats+0x122/0x230 [hfi1]
[   62.648703]  ? hfi1_alloc_rn+0x40/0x40 [hfi1]
[   62.655088]  ? __kmalloc+0x110/0x240
[   62.660695]  ? hfi1_alloc_rn+0x40/0x40 [hfi1]
[   62.667142]  setup_hw_stats+0xd8/0x430 [ib_core]
[   62.673972]  ? show_hfi+0x50/0x50 [hfi1]
[   62.680026]  ib_device_register_sysfs+0x165/0x180 [ib_core]
[   62.687995]  ib_register_device+0x5a2/0xa10 [ib_core]
[   62.695340]  ? show_hfi+0x50/0x50 [hfi1]
[   62.701421]  ? ib_unregister_device+0x2e0/0x2e0 [ib_core]
[   62.709222]  ? __vmalloc_node_range+0x2d0/0x380
[   62.716131]  ? rvt_driver_mr_init+0x11f/0x2d0 [rdmavt]
[   62.723735]  ? vmalloc_node+0x5c/0x70
[   62.729697]  ? rvt_driver_mr_init+0x11f/0x2d0 [rdmavt]
[   62.737347]  ? rvt_driver_mr_init+0x1f5/0x2d0 [rdmavt]
[   62.744998]  ? __rvt_alloc_mr+0x110/0x110 [rdmavt]
[   62.752315]  ? rvt_rc_error+0x140/0x140 [rdmavt]
[   62.759434]  ? rvt_vma_open+0x30/0x30 [rdmavt]
[   62.766364]  ? mutex_unlock+0x1d/0x40
[   62.772445]  ? kmem_cache_create_usercopy+0x15d/0x230
[   62.780115]  rvt_register_device+0x1f6/0x360 [rdmavt]
[   62.787823]  ? rvt_get_port_immutable+0x180/0x180 [rdmavt]
[   62.796058]  ? __get_txreq+0x400/0x400 [hfi1]
[   62.802969]  ? memcpy+0x34/0x50
[   62.808611]  hfi1_register_ib_device+0xde6/0xeb0 [hfi1]
[   62.816601]  ? hfi1_get_npkeys+0x10/0x10 [hfi1]
[   62.823760]  ? hfi1_init+0x89f/0x9a0 [hfi1]
[   62.830469]  ? hfi1_setup_eagerbufs+0xad0/0xad0 [hfi1]
[   62.838204]  ? pcie_capability_clear_and_set_word+0xcd/0xe0
[   62.846429]  ? pcie_capability_read_word+0xd0/0xd0
[   62.853791]  ? hfi1_pcie_init+0x187/0x4b0 [hfi1]
[   62.860958]  init_one+0x67f/0xae0 [hfi1]
[   62.867301]  ? hfi1_init+0x9a0/0x9a0 [hfi1]
[   62.873876]  ? wait_woken+0x130/0x130
[   62.879860]  ? read_word_at_a_time+0xe/0x20
[   62.886329]  ? strscpy+0x14b/0x280
[   62.891998]  ? hfi1_init+0x9a0/0x9a0 [hfi1]
[   62.898405]  local_pci_probe+0x70/0xd0
[   62.904295]  ? pci_device_shutdown+0x90/0x90
[   62.910833]  work_for_cpu_fn+0x29/0x40
[   62.916750]  process_one_work+0x584/0x960
[   62.922974]  ? rcu_work_rcufn+0x40/0x40
[   62.928991]  ? __schedule+0x396/0xdc0
[   62.934806]  ? __sched_text_start+0x8/0x8
[   62.941020]  ? pick_next_task_fair+0x68b/0xc60
[   62.947674]  ? run_rebalance_domains+0x260/0x260
[   62.954471]  ? __list_add_valid+0x29/0xa0
[   62.960607]  ? move_linked_works+0x1c7/0x230
[   62.967077]  ?
trace_event_raw_event_workqueue_execute_start+0x140/0x140
[   62.976248]  ? mutex_lock+0xa6/0x100
[   62.982029]  ? __mutex_lock_slowpath+0x10/0x10
[   62.988795]  ? __switch_to+0x37a/0x710
[   62.994731]  worker_thread+0x62e/0x9d0
[   63.000602]  ? max_active_store+0xf0/0xf0
[   63.006828]  ? __switch_to_asm+0x40/0x70
[   63.012932]  ? __switch_to_asm+0x34/0x70
[   63.019013]  ? __switch_to_asm+0x40/0x70
[   63.025042]  ? __switch_to_asm+0x34/0x70
[   63.031030]  ? __switch_to_asm+0x40/0x70
[   63.037006]  ? __schedule+0x396/0xdc0
[   63.042660]  ? kmem_cache_alloc_trace+0xf3/0x1f0
[   63.049323]  ? kthread+0x59/0x1d0
[   63.054594]  ? ret_from_fork+0x35/0x40
[   63.060257]  ? __sched_text_start+0x8/0x8
[   63.066212]  ? schedule+0xcf/0x250
[   63.071529]  ? __wake_up_common+0x110/0x350
[   63.077794]  ? __schedule+0xdc0/0xdc0
[   63.083348]  ? wait_woken+0x130/0x130
[   63.088963]  ? finish_task_switch+0x1f1/0x520
[   63.095258]  ? kasan_unpoison_shadow+0x30/0x40
[   63.101792]  ? __init_waitqueue_head+0xa0/0xd0
[   63.108183]  ? replenish_dl_entity.cold.60+0x18/0x18
[   63.115151]  ? _raw_spin_lock_irqsave+0x25/0x50
[   63.121754]  ? max_active_store+0xf0/0xf0
[   63.127753]  kthread+0x1ae/0x1d0
[   63.132894]  ? kthread_bind+0x30/0x30
[   63.138422]  ret_from_fork+0x35/0x40

[   63.146973] Allocated by task 14:
[   63.152077]  kasan_kmalloc+0xbf/0xe0
[   63.157471]  __kmalloc+0x110/0x240
[   63.162804]  init_cntrs+0x34d/0xdf0 [hfi1]
[   63.168883]  hfi1_init_dd+0x29a3/0x2f90 [hfi1]
[   63.175244]  init_one+0x551/0xae0 [hfi1]
[   63.181065]  local_pci_probe+0x70/0xd0
[   63.186759]  work_for_cpu_fn+0x29/0x40
[   63.192310]  process_one_work+0x584/0x960
[   63.198163]  worker_thread+0x62e/0x9d0
[   63.203843]  kthread+0x1ae/0x1d0
[   63.208874]  ret_from_fork+0x35/0x40

[   63.217203] Freed by task 1:
[   63.221844]  __kasan_slab_free+0x12e/0x180
[   63.227844]  kfree+0x92/0x1a0
[   63.232570]  single_release+0x3a/0x60
[   63.238024]  __fput+0x1d9/0x480
[   63.242911]  task_work_run+0x139/0x190
[   63.248440]  exit_to_usermode_loop+0x191/0x1a0
[   63.254814]  do_syscall_64+0x301/0x330
[   63.260283]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[   63.270199] The buggy address belongs to the object at
ffff88080e8d5500
 which belongs to the cache kmalloc-4096 of size 4096
[   63.287247] The buggy address is located 3632 bytes inside of
 4096-byte region [ffff88080e8d5500, ffff88080e8d6500)
[   63.303564] The buggy address belongs to the page:
[   63.310447] page:ffffea00203a3400 count:1 mapcount:0
mapping:ffff88081380e840 index:0x0 compound_mapcount: 0
[   63.323102] flags: 0x2fffff80008100(slab|head)
[   63.329775] raw: 002fffff80008100 0000000000000000 0000000100000001
ffff88081380e840
[   63.340175] raw: 0000000000000000 0000000000070007 00000001ffffffff
0000000000000000
[   63.350564] page dumped because: kasan: bad access detected

[   63.361974] Memory state around the buggy address:
[   63.369137]  ffff88080e8d6200: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
[   63.379082]  ffff88080e8d6280: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
[   63.389032] &gt;ffff88080e8d6300: 00 00 00 00 00 00 fc fc fc fc fc fc fc
fc fc fc
[   63.398944]                                      ^
[   63.406141]  ffff88080e8d6380: fc fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc
[   63.416109]  ffff88080e8d6400: fc fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc
[   63.426099]
==================================================================

The trace happens because get_hw_stats() assumes there is room in the
memory allocated in init_cntrs() to accommodate the driver counters.
Unfortunately, that routine only allocated space for the device
counters.

Fix by insuring the allocation has room for the additional driver
counters.

Cc: &lt;Stable@vger.kernel.org&gt; # v4.14+
Fixes: b7481944b06e9 ("IB/hfi1: Show statistics counters under IB stats interface")
Reviewed-by: Mike Marciniczyn &lt;mike.marciniszyn@intel.com&gt;
Reviewed-by: Mike Ruhl &lt;michael.j.ruhl@intel.com&gt;
Signed-off-by: Piotr Stankiewicz &lt;piotr.stankiewicz@intel.com&gt;
Signed-off-by: Dennis Dalessandro &lt;dennis.dalessandro@intel.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ALSA: hda/realtek - Fixed headphone issue for ALC700</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Kailang Yang</name>
<email>kailang@realtek.com</email>
</author>
<published>2018-12-07T07:14:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=d655a1a6684e0d6cc2429caeb4c5dd0fed4efb79'/>
<id>urn:sha1:d655a1a6684e0d6cc2429caeb4c5dd0fed4efb79</id>
<content type='text'>
commit bde1a7459623a66c2abec4d0a841e4b06cc88d9a upstream.

If it plugged headphone or headset into the jack, then
do the reboot, it will have a chance to cause headphone no sound.
It just need to run the headphone mode procedure after boot time.
The issue will be fixed.
It also suitable for ALC234 ALC274 and ALC294.

Signed-off-by: Kailang Yang &lt;kailang@realtek.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ALSA: fireface: fix reference to wrong register for clock configuration</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Takashi Sakamoto</name>
<email>o-takashi@sakamocchi.jp</email>
</author>
<published>2018-12-09T08:04:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=62711dc6898b3186a8a3501e4a3829add8624b3f'/>
<id>urn:sha1:62711dc6898b3186a8a3501e4a3829add8624b3f</id>
<content type='text'>
commit fa9c98e4b975bb3192ed6af09d9fa282ed3cd8a0 upstream.

In an initial commit, 'SYNC_STATUS' register is referred to get
clock configuration, however this is wrong, according to my local
note at hand for reverse-engineering about packet dump. It should
be 'CLOCK_CONFIG' register. Actually, ff400_dump_clock_config()
is correctly programmed.

This commit fixes the bug.

Cc: &lt;stable@vger.kernel.org&gt; # v4.12+
Fixes: 76fdb3a9e13a ('ALSA: fireface: add support for Fireface 400')
Signed-off-by: Takashi Sakamoto &lt;o-takashi@sakamocchi.jp&gt;
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>staging: speakup: Replace strncpy with memcpy</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Guenter Roeck</name>
<email>linux@roeck-us.net</email>
</author>
<published>2018-07-01T20:57:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=16906e5ad4cc0439d03dc294c0251f4c875ccef2'/>
<id>urn:sha1:16906e5ad4cc0439d03dc294c0251f4c875ccef2</id>
<content type='text'>
commit fd29edc7232bc19f969e8f463138afc5472b3d5f upstream.

gcc 8.1.0 generates the following warnings.

drivers/staging/speakup/kobjects.c: In function 'punc_store':
drivers/staging/speakup/kobjects.c:522:2: warning:
	'strncpy' output truncated before terminating nul
	copying as many bytes from a string as its length
drivers/staging/speakup/kobjects.c:504:6: note: length computed here

drivers/staging/speakup/kobjects.c: In function 'synth_store':
drivers/staging/speakup/kobjects.c:391:2: warning:
	'strncpy' output truncated before terminating nul
	copying as many bytes from a string as its length
drivers/staging/speakup/kobjects.c:388:8: note: length computed here

Using strncpy() is indeed less than perfect since the length of data to
be copied has already been determined with strlen(). Replace strncpy()
with memcpy() to address the warning and optimize the code a little.

Signed-off-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Reviewed-by: Samuel Thibault &lt;samuel.thibault@ens-lyon.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>flexfiles: enforce per-mirror stateid only for v4 DSes</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Tigran Mkrtchyan</name>
<email>tigran.mkrtchyan@desy.de</email>
</author>
<published>2018-11-26T17:35:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5d2cc520d1f1ed929ef1f6b7ad57ddde9c42b651'/>
<id>urn:sha1:5d2cc520d1f1ed929ef1f6b7ad57ddde9c42b651</id>
<content type='text'>
commit 320f35b7bf8cccf1997ca3126843535e1b95e9c4 upstream.

Since commit bb21ce0ad227 we always enforce per-mirror stateid.
However, this makes sense only for v4+ servers.

Signed-off-by: Tigran Mkrtchyan &lt;tigran.mkrtchyan@desy.de&gt;
Signed-off-by: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>lib/rbtree-test: lower default params</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Davidlohr Bueso</name>
<email>dave@stgolabs.net</email>
</author>
<published>2017-11-17T23:28:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=891e5a89f0faf42766eefd476285d4779fd31a21'/>
<id>urn:sha1:891e5a89f0faf42766eefd476285d4779fd31a21</id>
<content type='text'>
commit 0b548e33e6cb2bff240fdaf1783783be15c29080 upstream.

Fengguang reported soft lockups while running the rbtree and interval
tree test modules.  The logic for these tests all occur in init phase,
and we currently are pounding with the default values for number of
nodes and number of iterations of each test.  Reduce the latter by two
orders of magnitude.  This does not influence the value of the tests in
that one thousand times by default is enough to get the picture.

Link: http://lkml.kernel.org/r/20171109161715.xai2dtwqw2frhkcm@linux-n805
Signed-off-by: Davidlohr Bueso &lt;dbueso@suse.de&gt;
Reported-by: Fengguang Wu &lt;fengguang.wu@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>printk: Wake klogd when passing console_lock owner</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Petr Mladek</name>
<email>pmladek@suse.com</email>
</author>
<published>2018-02-26T14:44:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=16c9a316f21f1bcde5ce0633848d61699d63bad3'/>
<id>urn:sha1:16c9a316f21f1bcde5ce0633848d61699d63bad3</id>
<content type='text'>
[ Upstream commit c14376de3a1befa70d9811ca2872d47367b48767 ]

wake_klogd is a local variable in console_unlock(). The information
is lost when the console_lock owner using the busy wait added by
the commit dbdda842fe96f8932 ("printk: Add console owner and waiter
logic to load balance console writes"). The following race is
possible:

CPU0				CPU1
console_unlock()

  for (;;)
     /* calling console for last message */

				printk()
				  log_store()
				    log_next_seq++;

     /* see new message */
     if (seen_seq != log_next_seq) {
	wake_klogd = true;
	seen_seq = log_next_seq;
     }

     console_lock_spinning_enable();

				  if (console_trylock_spinning())
				     /* spinning */

     if (console_lock_spinning_disable_and_check()) {
	printk_safe_exit_irqrestore(flags);
	return;

				  console_unlock()
				    if (seen_seq != log_next_seq) {
				    /* already seen */
				    /* nothing to do */

Result: Nobody would wakeup klogd.

One solution would be to make a global variable from wake_klogd.
But then we would need to manipulate it under a lock or so.

This patch wakes klogd also when console_lock is passed to the
spinning waiter. It looks like the right way to go. Also userspace
should have a chance to see and store any "flood" of messages.

Note that the very late klogd wake up was a historic solution.
It made sense on single CPU systems or when sys_syslog() operations
were synchronized using the big kernel lock like in v2.1.113.
But it is questionable these days.

Fixes: dbdda842fe96f8932 ("printk: Add console owner and waiter logic to load balance console writes")
Link: http://lkml.kernel.org/r/20180226155734.dzwg3aovqnwtvkoy@pathway.suse.cz
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: linux-kernel@vger.kernel.org
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Suggested-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Signed-off-by: Petr Mladek &lt;pmladek@suse.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>printk: Never set console_may_schedule in console_trylock()</title>
<updated>2018-12-17T08:28:55+00:00</updated>
<author>
<name>Sergey Senozhatsky</name>
<email>sergey.senozhatsky.work@gmail.com</email>
</author>
<published>2018-01-16T04:47:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=08b7a8f880a27631e25e23ac2569f7c2d166469e'/>
<id>urn:sha1:08b7a8f880a27631e25e23ac2569f7c2d166469e</id>
<content type='text'>
[ Upstream commit fd5f7cde1b85d4c8e09ca46ce948e008a2377f64 ]

This patch, basically, reverts commit 6b97a20d3a79 ("printk:
set may_schedule for some of console_trylock() callers").
That commit was a mistake, it introduced a big dependency
on the scheduler, by enabling preemption under console_sem
in printk()-&gt;console_unlock() path, which is rather too
critical. The patch did not significantly reduce the
possibilities of printk() lockups, but made it possible to
stall printk(), as has been reported by Tetsuo Handa [1].

Another issues is that preemption under console_sem also
messes up with Steven Rostedt's hand off scheme, by making
it possible to sleep with console_sem both in console_unlock()
and in vprintk_emit(), after acquiring the console_sem
ownership (anywhere between printk_safe_exit_irqrestore() in
console_trylock_spinning() and printk_safe_enter_irqsave()
in console_unlock()). This makes hand off less likely and,
at the same time, may result in a significant amount of
pending logbuf messages. Preempted console_sem owner makes
it impossible for other CPUs to emit logbuf messages, but
does not make it impossible for other CPUs to append new
messages to the logbuf.

Reinstate the old behavior and make printk() non-preemptible.
Should any printk() lockup reports arrive they must be handled
in a different way.

[1] http://lkml.kernel.org/r/201603022101.CAH73907.OVOOMFHFFtQJSL%20()%20I-love%20!%20SAKURA%20!%20ne%20!%20jp
Fixes: 6b97a20d3a79 ("printk: set may_schedule for some of console_trylock() callers")
Link: http://lkml.kernel.org/r/20180116044716.GE6607@jagdpanzerIV
To: Tetsuo Handa &lt;penguin-kernel@I-love.SAKURA.ne.jp&gt;
Cc: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Cc: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Cc: Dave Hansen &lt;dave.hansen@intel.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Byungchul Park &lt;byungchul.park@lge.com&gt;
Cc: Pavel Machek &lt;pavel@ucw.cz&gt;
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Reported-by: Tetsuo Handa &lt;penguin-kernel@I-love.SAKURA.ne.jp&gt;
Reviewed-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Petr Mladek &lt;pmladek@suse.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
</feed>
