[PATCH for-4.9.y 00/14] Few upstream fixes from OnePlus6's kernel tree

[PATCH for-4.9.y 00/14] Few upstream fixes from OnePlus6's kernel tree

[Amit Pundir]

Hi Greg,

For your consideration, few upstream fixes picked up from
Qcom's android-4.9 BSP tree for OnePlus 6 device.

Cherry-picked and build tested for ARCH=x86_64/mips on v4.9.124.
Few patches are applicable for 4.4.y and 3.18.y as well and
explicitly marked so respectively.

Regards,
Amit Pundir


Daniel Micay (1):
  staging/rts5208: Fix read overflow in memcpy

Jason A. Donenfeld (1):
  random: convert get_random_int/long into get_random_u32/u64

Jia-Ju Bai (1):
  staging: rt5208: Fix a sleep-in-atomic bug in xd_copy_page

Johannes Berg (1):
  nl80211: fix null-ptr dereference on invalid mesh configuration

Johannes Weiner (1):
  mm: remove seemingly spurious reclaimability check from laptop_mode
    gating

Kees Cook (1):
  IB/rxe: do not copy extra stack memory to skb

Mel Gorman (1):
  mm, vmscan: clear PGDAT_WRITEBACK when zone is balanced

Michal Hocko (1):
  selinux: use GFP_NOWAIT in the AVC kmem_caches

Prateek Sood (2):
  locking/rwsem-xadd: Fix missed wakeup due to reordering of load
  locking/osq_lock: Fix osq_lock queue corruption

Ritesh Harjani (1):
  cfq: Give a chance for arming slice idle timer in case of group_idle

Tejun Heo (1):
  block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg

Vegard Nossum (2):
  kthread: Fix use-after-free if kthread fork fails
  kthread: fix boot hang (regression) on MIPS/OpenRISC

 arch/mips/kernel/process.c           |  1 -
 arch/openrisc/kernel/process.c       |  2 --
 block/blk-cgroup.c                   |  9 +++---
 block/cfq-iosched.c                  |  6 ++--
 drivers/char/random.c                | 55 ++++++++++++++++++------------------
 drivers/infiniband/sw/rxe/rxe_resp.c |  4 ++-
 drivers/staging/rts5208/rtsx_scsi.c  |  2 +-
 drivers/staging/rts5208/xd.c         |  2 +-
 include/linux/random.h               | 17 +++++++++--
 kernel/fork.c                        | 17 +++++++----
 kernel/locking/osq_lock.c            | 13 +++++++++
 kernel/locking/rwsem-xadd.c          | 27 ++++++++++++++++++
 mm/vmscan.c                          |  3 +-
 net/wireless/nl80211.c               |  3 ++
 security/selinux/avc.c               | 14 ++++-----
 15 files changed, 119 insertions(+), 56 deletions(-)

-- 
2.7.4

[PATCH for-4.9.y 01/14] cfq: Give a chance for arming slice idle timer in case of group_idle

[Amit Pundir]

From: Ritesh Harjani <riteshh@codeaurora.org>

commit b3193bc0dca9bb69c8ba1ec1a318105c76eb4172 upstream.

In below scenario blkio cgroup does not work as per their assigned
weights :-
1. When the underlying device is nonrotational with a single HW queue
with depth of >= CFQ_HW_QUEUE_MIN
2. When the use case is forming two blkio cgroups cg1(weight 1000) &
cg2(wight 100) and two processes(file1 and file2) doing sync IO in
their respective blkio cgroups.

For above usecase result of fio (without this patch):-
file1: (groupid=0, jobs=1): err= 0: pid=685: Thu Jan  1 19:41:49 1970
  write: IOPS=1315, BW=41.1MiB/s (43.1MB/s)(1024MiB/24906msec)
<...>
file2: (groupid=0, jobs=1): err= 0: pid=686: Thu Jan  1 19:41:49 1970
  write: IOPS=1295, BW=40.5MiB/s (42.5MB/s)(1024MiB/25293msec)
<...>
// both the process BW is equal even though they belong to diff.
cgroups with weight of 1000(cg1) and 100(cg2)

In above case (for non rotational NCQ devices),
as soon as the request from cg1 is completed and even
though it is provided with higher set_slice=10, because of CFQ
algorithm when the driver tries to fetch the request, CFQ expires
this group without providing any idle time nor weight priority
and schedules another cfq group (in this case cg2).
And thus both cfq groups(cg1 & cg2) keep alternating to get the
disk time and hence loses the cgroup weight based scheduling.

Below patch gives a chance to cfq algorithm (cfq_arm_slice_timer)
to arm the slice timer in case group_idle is enabled.
In case if group_idle is also not required (including for nonrotational
NCQ drives), we need to explicitly set group_idle = 0 from sysfs for
such cases.

With this patch result of fio(for above usecase) :-
file1: (groupid=0, jobs=1): err= 0: pid=690: Thu Jan  1 00:06:08 1970
  write: IOPS=1706, BW=53.3MiB/s (55.9MB/s)(1024MiB/19197msec)
<..>
file2: (groupid=0, jobs=1): err= 0: pid=691: Thu Jan  1 00:06:08 1970
  write: IOPS=1043, BW=32.6MiB/s (34.2MB/s)(1024MiB/31401msec)
<..>
// In this processes BW is as per their respective cgroups weight.

Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y and 3.18.y as well.
Build tested on v4.4.153 and v3.18.120.

 block/cfq-iosched.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index c7c3d4e6bc27..b2dc1c1f08c6 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2951,7 +2951,8 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	 * for devices that support queuing, otherwise we still have a problem
 	 * with sync vs async workloads.
 	 */
-	if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)
+	if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag &&
+		!cfqd->cfq_group_idle)
 		return;
 
 	WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
-- 
2.7.4

[PATCH for-4.9.y 02/14] kthread: Fix use-after-free if kthread fork fails

[Amit Pundir]

From: Vegard Nossum <vegard.nossum@oracle.com>

commit 4d6501dce079c1eb6bf0b1d8f528a5e81770109e upstream.

If a kthread forks (e.g. usermodehelper since commit 1da5c46fa965) but
fails in copy_process() between calling dup_task_struct() and setting
p->set_child_tid, then the value of p->set_child_tid will be inherited
from the parent and get prematurely freed by free_kthread_struct().

    kthread()
     - worker_thread()
        - process_one_work()
        |  - call_usermodehelper_exec_work()
        |     - kernel_thread()
        |        - _do_fork()
        |           - copy_process()
        |              - dup_task_struct()
        |                 - arch_dup_task_struct()
        |                    - tsk->set_child_tid = current->set_child_tid // implied
        |              - ...
        |              - goto bad_fork_*
        |              - ...
        |              - free_task(tsk)
        |                 - free_kthread_struct(tsk)
        |                    - kfree(tsk->set_child_tid)
        - ...
        - schedule()
           - __schedule()
              - wq_worker_sleeping()
                 - kthread_data(task)->flags // UAF

The problem started showing up with commit 1da5c46fa965 since it reused
->set_child_tid for the kthread worker data.

A better long-term solution might be to get rid of the ->set_child_tid
abuse. The comment in set_kthread_struct() also looks slightly wrong.

Debugged-by: Jamie Iles <jamie.iles@oracle.com>
Fixes: 1da5c46fa965 ("kthread: Make struct kthread kmalloc'ed")
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jamie Iles <jamie.iles@oracle.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170509073959.17858-1-vegard.nossum@oracle.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y and 3.18.y as well.
Build tested on v4.4.153 and v3.18.120.

 kernel/fork.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 2c98b987808d..46a6b0311ca3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1530,6 +1530,18 @@ static __latent_entropy struct task_struct *copy_process(
 	if (!p)
 		goto fork_out;
 
+	/*
+	 * This _must_ happen before we call free_task(), i.e. before we jump
+	 * to any of the bad_fork_* labels. This is to avoid freeing
+	 * p->set_child_tid which is (ab)used as a kthread's data pointer for
+	 * kernel threads (PF_KTHREAD).
+	 */
+	p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
+	/*
+	 * Clear TID on mm_release()?
+	 */
+	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL;
+
 	ftrace_graph_init_task(p);
 
 	rt_mutex_init_task(p);
@@ -1691,11 +1703,6 @@ static __latent_entropy struct task_struct *copy_process(
 		}
 	}
 
-	p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
-	/*
-	 * Clear TID on mm_release()?
-	 */
-	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL;
 #ifdef CONFIG_BLOCK
 	p->plug = NULL;
 #endif
-- 
2.7.4

[PATCH for-4.9.y 03/14] kthread: fix boot hang (regression) on MIPS/OpenRISC

[Amit Pundir]

From: Vegard Nossum <vegard.nossum@oracle.com>

commit b0f5a8f32e8bbdaae1abb8abe2d3cbafaba57e08 upstream.

This fixes a regression in commit 4d6501dce079 where I didn't notice
that MIPS and OpenRISC were reinitialising p->{set,clear}_child_tid to
NULL after our initialisation in copy_process().

We can simply get rid of the arch-specific initialisation here since it
is now always done in copy_process() before hitting copy_thread{,_tls}().

Review notes:

 - As far as I can tell, copy_process() is the only user of
   copy_thread_tls(), which is the only caller of copy_thread() for
   architectures that don't implement copy_thread_tls().

 - After this patch, there is no arch-specific code touching
   p->set_child_tid or p->clear_child_tid whatsoever.

 - It may look like MIPS/OpenRISC wanted to always have these fields be
   NULL, but that's not true, as copy_process() would unconditionally
   set them again _after_ calling copy_thread_tls() before commit
   4d6501dce079.

Fixes: 4d6501dce079c1eb6bf0b1d8f528a5e81770109e ("kthread: Fix use-after-free if kthread fork fails")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net> # MIPS only
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: openrisc@lists.librecores.org
Cc: Jamie Iles <jamie.iles@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y and 3.18.y as well.
Build tested on v4.4.153 and v3.18.120.

 arch/mips/kernel/process.c     | 1 -
 arch/openrisc/kernel/process.c | 2 --
 2 files changed, 3 deletions(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 513a63b9b991..ba315e523b33 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -118,7 +118,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	struct thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs, *regs = current_pt_regs();
 	unsigned long childksp;
-	p->set_child_tid = p->clear_child_tid = NULL;
 
 	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
 
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index 7095dfe7666b..962372143fda 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -152,8 +152,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
 
 	top_of_kernel_stack = sp;
 
-	p->set_child_tid = p->clear_child_tid = NULL;
-
 	/* Locate userspace context on stack... */
 	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
 	sp -= sizeof(struct pt_regs);
-- 
2.7.4

[PATCH for-4.9.y 04/14] random: convert get_random_int/long into get_random_u32/u64

[Amit Pundir]

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

commit c440408cf6901eeb2c09563397e24a9097907078 upstream.

Many times, when a user wants a random number, he wants a random number
of a guaranteed size. So, thinking of get_random_int and get_random_long
in terms of get_random_u32 and get_random_u64 makes it much easier to
achieve this. It also makes the code simpler.

On 32-bit platforms, get_random_int and get_random_long are both aliased
to get_random_u32. On 64-bit platforms, int->u32 and long->u64.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
 drivers/char/random.c  | 55 +++++++++++++++++++++++++-------------------------
 include/linux/random.h | 17 ++++++++++++++--
 2 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 81b65d0e7563..464b95a63dc5 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2110,8 +2110,8 @@ struct ctl_table random_table[] = {
 
 struct batched_entropy {
 	union {
-		unsigned long entropy_long[CHACHA20_BLOCK_SIZE / sizeof(unsigned long)];
-		unsigned int entropy_int[CHACHA20_BLOCK_SIZE / sizeof(unsigned int)];
+		u64 entropy_u64[CHACHA20_BLOCK_SIZE / sizeof(u64)];
+		u32 entropy_u32[CHACHA20_BLOCK_SIZE / sizeof(u32)];
 	};
 	unsigned int position;
 };
@@ -2121,52 +2121,51 @@ struct batched_entropy {
  * number is either as good as RDRAND or as good as /dev/urandom, with the
  * goal of being quite fast and not depleting entropy.
  */
-static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_long);
-unsigned long get_random_long(void)
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64);
+u64 get_random_u64(void)
 {
-	unsigned long ret;
+	u64 ret;
 	struct batched_entropy *batch;
 
-	if (arch_get_random_long(&ret))
+#if BITS_PER_LONG == 64
+	if (arch_get_random_long((unsigned long *)&ret))
 		return ret;
+#else
+	if (arch_get_random_long((unsigned long *)&ret) &&
+	    arch_get_random_long((unsigned long *)&ret + 1))
+	    return ret;
+#endif
 
-	batch = &get_cpu_var(batched_entropy_long);
-	if (batch->position % ARRAY_SIZE(batch->entropy_long) == 0) {
-		extract_crng((u8 *)batch->entropy_long);
+	batch = &get_cpu_var(batched_entropy_u64);
+	if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) {
+		extract_crng((u8 *)batch->entropy_u64);
 		batch->position = 0;
 	}
-	ret = batch->entropy_long[batch->position++];
-	put_cpu_var(batched_entropy_long);
+	ret = batch->entropy_u64[batch->position++];
+	put_cpu_var(batched_entropy_u64);
 	return ret;
 }
-EXPORT_SYMBOL(get_random_long);
+EXPORT_SYMBOL(get_random_u64);
 
-#if BITS_PER_LONG == 32
-unsigned int get_random_int(void)
-{
-	return get_random_long();
-}
-#else
-static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_int);
-unsigned int get_random_int(void)
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32);
+u32 get_random_u32(void)
 {
-	unsigned int ret;
+	u32 ret;
 	struct batched_entropy *batch;
 
 	if (arch_get_random_int(&ret))
 		return ret;
 
-	batch = &get_cpu_var(batched_entropy_int);
-	if (batch->position % ARRAY_SIZE(batch->entropy_int) == 0) {
-		extract_crng((u8 *)batch->entropy_int);
+	batch = &get_cpu_var(batched_entropy_u32);
+	if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) {
+		extract_crng((u8 *)batch->entropy_u32);
 		batch->position = 0;
 	}
-	ret = batch->entropy_int[batch->position++];
-	put_cpu_var(batched_entropy_int);
+	ret = batch->entropy_u32[batch->position++];
+	put_cpu_var(batched_entropy_u32);
 	return ret;
 }
-#endif
-EXPORT_SYMBOL(get_random_int);
+EXPORT_SYMBOL(get_random_u32);
 
 /**
  * randomize_page - Generate a random, page aligned address
diff --git a/include/linux/random.h b/include/linux/random.h
index 16ab429735a7..ed5c3838780d 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -42,8 +42,21 @@ extern void get_random_bytes_arch(void *buf, int nbytes);
 extern const struct file_operations random_fops, urandom_fops;
 #endif
 
-unsigned int get_random_int(void);
-unsigned long get_random_long(void);
+u32 get_random_u32(void);
+u64 get_random_u64(void);
+static inline unsigned int get_random_int(void)
+{
+	return get_random_u32();
+}
+static inline unsigned long get_random_long(void)
+{
+#if BITS_PER_LONG == 64
+	return get_random_u64();
+#else
+	return get_random_u32();
+#endif
+}
+
 unsigned long randomize_page(unsigned long start, unsigned long range);
 
 u32 prandom_u32(void);
-- 
2.7.4

Re: [PATCH for-4.9.y 04/14] random: convert get_random_int/long into get_random_u32/u64

[Greg KH]

On Wed, Aug 29, 2018 at 01:43:15AM +0530, Amit Pundir wrote:
> From: "Jason A. Donenfeld" <Jason@zx2c4.com>
> 
> commit c440408cf6901eeb2c09563397e24a9097907078 upstream.
> 
> Many times, when a user wants a random number, he wants a random number
> of a guaranteed size. So, thinking of get_random_int and get_random_long
> in terms of get_random_u32 and get_random_u64 makes it much easier to
> achieve this. It also makes the code simpler.
> 
> On 32-bit platforms, get_random_int and get_random_long are both aliased
> to get_random_u32. On 64-bit platforms, int->u32 and long->u64.

What bug is this fixing that it needs to be in a stable kernel tree?
The end result is the same before and after this patch, right?

thanks,

greg k-h

[PATCH for-4.9.y 05/14] staging: rt5208: Fix a sleep-in-atomic bug in xd_copy_page

[Amit Pundir]

From: Jia-Ju Bai <baijiaju1990@163.com>

commit 498c4b4e9c23855d17ecc2a108d949bb68020481 upstream.

The driver may sleep under a spin lock, and the function call path is:
rtsx_exclusive_enter_ss (acquire the lock by spin_lock)
  rtsx_enter_ss
    rtsx_power_off_card
      xd_cleanup_work
        xd_delay_write
          xd_finish_write
            xd_copy_page
              wait_timeout
                schedule_timeout --> may sleep

To fix it, "wait_timeout" is replaced with mdelay in xd_copy_page.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y and 3.18.y as well.
Build tested on v4.4.153 and v3.18.120.

 drivers/staging/rts5208/xd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rts5208/xd.c b/drivers/staging/rts5208/xd.c
index 1de02bb98839..647f6beb4c65 100644
--- a/drivers/staging/rts5208/xd.c
+++ b/drivers/staging/rts5208/xd.c
@@ -1247,7 +1247,7 @@ static int xd_copy_page(struct rtsx_chip *chip, u32 old_blk, u32 new_blk,
 			reg = 0;
 			rtsx_read_register(chip, XD_CTL, &reg);
 			if (reg & (XD_ECC1_ERROR | XD_ECC2_ERROR)) {
-				wait_timeout(100);
+				mdelay(100);
 
 				if (detect_card_cd(chip,
 					XD_CARD) != STATUS_SUCCESS) {
-- 
2.7.4

[PATCH for-4.9.y 06/14] staging/rts5208: Fix read overflow in memcpy

[Amit Pundir]

From: Daniel Micay <danielmicay@gmail.com>

commit 88a5b39b69ab1828fd4130e2baadd184109cea69 upstream.

Noticed by FORTIFY_SOURCE, this swaps memcpy() for strncpy() to zero-value
fill the end of the buffer instead of over-reading a string from .rodata.

Signed-off-by: Daniel Micay <danielmicay@gmail.com>
[kees: wrote commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Wayne Porter <wporter82@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y and 3.18.y as well.
Build tested on v4.4.153 and v3.18.120.

 drivers/staging/rts5208/rtsx_scsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rts5208/rtsx_scsi.c b/drivers/staging/rts5208/rtsx_scsi.c
index b3790334fd3f..f50076d0fb6c 100644
--- a/drivers/staging/rts5208/rtsx_scsi.c
+++ b/drivers/staging/rts5208/rtsx_scsi.c
@@ -536,7 +536,7 @@ static int inquiry(struct scsi_cmnd *srb, struct rtsx_chip *chip)
 
 	if (sendbytes > 8) {
 		memcpy(buf, inquiry_buf, 8);
-		memcpy(buf + 8, inquiry_string,	sendbytes - 8);
+		strncpy(buf + 8, inquiry_string, sendbytes - 8);
 		if (pro_formatter_flag) {
 			/* Additional Length */
 			buf[4] = 0x33;
-- 
2.7.4

[PATCH for-4.9.y 07/14] IB/rxe: do not copy extra stack memory to skb

[Amit Pundir]

From: Kees Cook <keescook@chromium.org>

commit 4c93496f18ce5044d78e4f7f9e018682a4f44b3d upstream.

This fixes a over-read condition detected by FORTIFY_SOURCE for this
line:

	memcpy(SKB_TO_PKT(skb), &ack_pkt, sizeof(skb->cb));

The error was:

  In file included from ./include/linux/bitmap.h:8:0,
                   from ./include/linux/cpumask.h:11,
                   from ./include/linux/mm_types_task.h:13,
                   from ./include/linux/mm_types.h:4,
                   from ./include/linux/kmemcheck.h:4,
                   from ./include/linux/skbuff.h:18,
                   from drivers/infiniband/sw/rxe/rxe_resp.c:34:
  In function 'memcpy',
      inlined from 'send_atomic_ack.constprop' at drivers/infiniband/sw/rxe/rxe_resp.c:998:2,
      inlined from 'acknowledge' at drivers/infiniband/sw/rxe/rxe_resp.c:1026:3,
      inlined from 'rxe_responder' at drivers/infiniband/sw/rxe/rxe_resp.c:1286:10:
  ./include/linux/string.h:309:4: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
      __read_overflow2();

Daniel Micay noted that struct rxe_pkt_info is 32 bytes on 32-bit
architectures, but skb->cb is still 64.  The memcpy() over-reads 32
bytes.  This fixes it by zeroing the unused bytes in skb->cb.

Link: http://lkml.kernel.org/r/1497903987-21002-5-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Moni Shoua <monis@mellanox.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
 drivers/infiniband/sw/rxe/rxe_resp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 0d25dc84d294..2152c71a99d3 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -978,7 +978,9 @@ static int send_atomic_ack(struct rxe_qp *qp, struct rxe_pkt_info *pkt,
 	free_rd_atomic_resource(qp, res);
 	rxe_advance_resp_resource(qp);
 
-	memcpy(SKB_TO_PKT(skb), &ack_pkt, sizeof(skb->cb));
+	memcpy(SKB_TO_PKT(skb), &ack_pkt, sizeof(ack_pkt));
+	memset((unsigned char *)SKB_TO_PKT(skb) + sizeof(ack_pkt), 0,
+	       sizeof(skb->cb) - sizeof(ack_pkt));
 
 	res->type = RXE_ATOMIC_MASK;
 	res->atomic.skb = skb;
-- 
2.7.4

[PATCH for-4.9.y 08/14] block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg

[Amit Pundir]

From: Tejun Heo <tj@kernel.org>

commit e00f4f4d0ff7e13b9115428a245b49108d625f09 upstream.

blkcg allocates some per-cgroup data structures with GFP_NOWAIT and
when that fails falls back to operations which aren't specific to the
cgroup.  Occassional failures are expected under pressure and falling
back to non-cgroup operation is the right thing to do.

Unfortunately, I forgot to add __GFP_NOWARN to these allocations and
these expected failures end up creating a lot of noise.  Add
__GFP_NOWARN.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Marc MERLIN <marc@merlins.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y as well.
Build tested on v4.4.153.

 block/blk-cgroup.c  | 9 +++++----
 block/cfq-iosched.c | 3 ++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 6cd839c1f507..f570f387034d 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -185,7 +185,8 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 	}
 
 	wb_congested = wb_congested_get_create(&q->backing_dev_info,
-					       blkcg->css.id, GFP_NOWAIT);
+					       blkcg->css.id,
+					       GFP_NOWAIT | __GFP_NOWARN);
 	if (!wb_congested) {
 		ret = -ENOMEM;
 		goto err_put_css;
@@ -193,7 +194,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
 
 	/* allocate */
 	if (!new_blkg) {
-		new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT);
+		new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN);
 		if (unlikely(!new_blkg)) {
 			ret = -ENOMEM;
 			goto err_put_congested;
@@ -1022,7 +1023,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
 	}
 
 	spin_lock_init(&blkcg->lock);
-	INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT);
+	INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN);
 	INIT_HLIST_HEAD(&blkcg->blkg_list);
 #ifdef CONFIG_CGROUP_WRITEBACK
 	INIT_LIST_HEAD(&blkcg->cgwb_list);
@@ -1238,7 +1239,7 @@ int blkcg_activate_policy(struct request_queue *q,
 		if (blkg->pd[pol->plid])
 			continue;
 
-		pd = pol->pd_alloc_fn(GFP_NOWAIT, q->node);
+		pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q->node);
 		if (!pd)
 			swap(pd, pd_prealloc);
 		if (!pd) {
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b2dc1c1f08c6..a4e2d0104af4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3868,7 +3868,8 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
 			goto out;
 	}
 
-	cfqq = kmem_cache_alloc_node(cfq_pool, GFP_NOWAIT | __GFP_ZERO,
+	cfqq = kmem_cache_alloc_node(cfq_pool,
+				     GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN,
 				     cfqd->queue->node);
 	if (!cfqq) {
 		cfqq = &cfqd->oom_cfqq;
-- 
2.7.4

[PATCH for-4.9.y 09/14] nl80211: fix null-ptr dereference on invalid mesh configuration

[Amit Pundir]

From: Johannes Berg <johannes.berg@intel.com>

commit 265698d7e6132a2d41471135534f4f36ad15b09c upstream.

If TX rates are specified during mesh join, the channel must
also be specified. Check the channel pointer to avoid a null
pointer dereference if it isn't.

Reported-by: Jouni Malinen <j@w1.fi>
Fixes: 8564e38206de ("cfg80211: add checks for beacon rate, extend to mesh")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
 net/wireless/nl80211.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 5b75468b5acd..d8002be808f2 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -9480,6 +9480,9 @@ static int nl80211_join_mesh(struct sk_buff *skb, struct genl_info *info)
 		if (err)
 			return err;
 
+		if (!setup.chandef.chan)
+			return -EINVAL;
+
 		err = validate_beacon_tx_rate(rdev, setup.chandef.chan->band,
 					      &setup.beacon_rate);
 		if (err)
-- 
2.7.4

[PATCH for-4.9.y 10/14] locking/rwsem-xadd: Fix missed wakeup due to reordering of load

[Amit Pundir]

From: Prateek Sood <prsood@codeaurora.org>

commit 9c29c31830a4eca724e137a9339137204bbb31be upstream.

If a spinner is present, there is a chance that the load of
rwsem_has_spinner() in rwsem_wake() can be reordered with
respect to decrement of rwsem count in __up_write() leading
to wakeup being missed:

 spinning writer                  up_write caller
 ---------------                  -----------------------
 [S] osq_unlock()                 [L] osq
  spin_lock(wait_lock)
  sem->count=0xFFFFFFFF00000001
            +0xFFFFFFFF00000000
  count=sem->count
  MB
                                   sem->count=0xFFFFFFFE00000001
                                             -0xFFFFFFFF00000001
                                   spin_trylock(wait_lock)
                                   return
 rwsem_try_write_lock(count)
 spin_unlock(wait_lock)
 schedule()

Reordering of atomic_long_sub_return_release() in __up_write()
and rwsem_has_spinner() in rwsem_wake() can cause missing of
wakeup in up_write() context. In spinning writer, sem->count
and local variable count is 0XFFFFFFFE00000001. It would result
in rwsem_try_write_lock() failing to acquire rwsem and spinning
writer going to sleep in rwsem_down_write_failed().

The smp_rmb() will make sure that the spinner state is
consulted after sem->count is updated in up_write context.

Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: longman@redhat.com
Cc: parri.andrea@gmail.com
Cc: sramana@codeaurora.org
Link: http://lkml.kernel.org/r/1504794658-15397-1-git-send-email-prsood@codeaurora.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y as well.
Build tested on v4.4.153.

 kernel/locking/rwsem-xadd.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 2337b4bb2366..a4112dfcd0fb 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -574,6 +574,33 @@ struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
 	WAKE_Q(wake_q);
 
 	/*
+	* __rwsem_down_write_failed_common(sem)
+	*   rwsem_optimistic_spin(sem)
+	*     osq_unlock(sem->osq)
+	*   ...
+	*   atomic_long_add_return(&sem->count)
+	*
+	*      - VS -
+	*
+	*              __up_write()
+	*                if (atomic_long_sub_return_release(&sem->count) < 0)
+	*                  rwsem_wake(sem)
+	*                    osq_is_locked(&sem->osq)
+	*
+	* And __up_write() must observe !osq_is_locked() when it observes the
+	* atomic_long_add_return() in order to not miss a wakeup.
+	*
+	* This boils down to:
+	*
+	* [S.rel] X = 1                [RmW] r0 = (Y += 0)
+	*         MB                         RMB
+	* [RmW]   Y += 1               [L]   r1 = X
+	*
+	* exists (r0=1 /\ r1=0)
+	*/
+	smp_rmb();
+
+	/*
 	 * If a spinner is present, it is not necessary to do the wakeup.
 	 * Try to do wakeup only if the trylock succeeds to minimize
 	 * spinlock contention which may introduce too much delay in the
-- 
2.7.4

[PATCH for-4.9.y 11/14] selinux: use GFP_NOWAIT in the AVC kmem_caches

[Amit Pundir]

From: Michal Hocko <mhocko@kernel.org>

commit 476accbe2f6ef69caeebe99f52a286e12ac35aee upstream.

There is a strange __GFP_NOMEMALLOC usage pattern in SELinux,
specifically GFP_ATOMIC | __GFP_NOMEMALLOC which doesn't make much
sense.  GFP_ATOMIC on its own allows to access memory reserves while
__GFP_NOMEMALLOC dictates we cannot use memory reserves.  Replace this
with the much more sane GFP_NOWAIT in the AVC code as we can tolerate
memory allocation failures in that code.

Signed-off-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y as well.
Build tested on v4.4.153.

 security/selinux/avc.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index e60c79de13e1..52f3c550abcc 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -348,27 +348,26 @@ static struct avc_xperms_decision_node
 	struct avc_xperms_decision_node *xpd_node;
 	struct extended_perms_decision *xpd;
 
-	xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep,
-				GFP_ATOMIC | __GFP_NOMEMALLOC);
+	xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, GFP_NOWAIT);
 	if (!xpd_node)
 		return NULL;
 
 	xpd = &xpd_node->xpd;
 	if (which & XPERMS_ALLOWED) {
 		xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_ATOMIC | __GFP_NOMEMALLOC);
+						GFP_NOWAIT);
 		if (!xpd->allowed)
 			goto error;
 	}
 	if (which & XPERMS_AUDITALLOW) {
 		xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_ATOMIC | __GFP_NOMEMALLOC);
+						GFP_NOWAIT);
 		if (!xpd->auditallow)
 			goto error;
 	}
 	if (which & XPERMS_DONTAUDIT) {
 		xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_ATOMIC | __GFP_NOMEMALLOC);
+						GFP_NOWAIT);
 		if (!xpd->dontaudit)
 			goto error;
 	}
@@ -396,8 +395,7 @@ static struct avc_xperms_node *avc_xperms_alloc(void)
 {
 	struct avc_xperms_node *xp_node;
 
-	xp_node = kmem_cache_zalloc(avc_xperms_cachep,
-				GFP_ATOMIC|__GFP_NOMEMALLOC);
+	xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT);
 	if (!xp_node)
 		return xp_node;
 	INIT_LIST_HEAD(&xp_node->xpd_head);
@@ -550,7 +548,7 @@ static struct avc_node *avc_alloc_node(void)
 {
 	struct avc_node *node;
 
-	node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC|__GFP_NOMEMALLOC);
+	node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT);
 	if (!node)
 		goto out;
 
-- 
2.7.4

[PATCH for-4.9.y 12/14] locking/osq_lock: Fix osq_lock queue corruption

[Amit Pundir]

From: Prateek Sood <prsood@codeaurora.org>

commit 50972fe78f24f1cd0b9d7bbf1f87d2be9e4f412e upstream.

Fix ordering of link creation between node->prev and prev->next in
osq_lock(). A case in which the status of optimistic spin queue is
CPU6->CPU2 in which CPU6 has acquired the lock.

        tail
          v
  ,-. <- ,-.
  |6|    |2|
  `-' -> `-'

At this point if CPU0 comes in to acquire osq_lock, it will update the
tail count.

  CPU2			CPU0
  ----------------------------------

				       tail
				         v
			  ,-. <- ,-.    ,-.
			  |6|    |2|    |0|
			  `-' -> `-'    `-'

After tail count update if CPU2 starts to unqueue itself from
optimistic spin queue, it will find an updated tail count with CPU0 and
update CPU2 node->next to NULL in osq_wait_next().

  unqueue-A

	       tail
	         v
  ,-. <- ,-.    ,-.
  |6|    |2|    |0|
  `-'    `-'    `-'

  unqueue-B

  ->tail != curr && !node->next

If reordering of following stores happen then prev->next where prev
being CPU2 would be updated to point to CPU0 node:

				       tail
				         v
			  ,-. <- ,-.    ,-.
			  |6|    |2|    |0|
			  `-'    `-' -> `-'

  osq_wait_next()
    node->next <- 0
    xchg(node->next, NULL)

	       tail
	         v
  ,-. <- ,-.    ,-.
  |6|    |2|    |0|
  `-'    `-'    `-'

  unqueue-C

At this point if next instruction
	WRITE_ONCE(next->prev, prev);
in CPU2 path is committed before the update of CPU0 node->prev = prev then
CPU0 node->prev will point to CPU6 node.

	       tail
    v----------. v
  ,-. <- ,-.    ,-.
  |6|    |2|    |0|
  `-'    `-'    `-'
     `----------^

At this point if CPU0 path's node->prev = prev is committed resulting
in change of CPU0 prev back to CPU2 node. CPU2 node->next is NULL
currently,

				       tail
			                 v
			  ,-. <- ,-. <- ,-.
			  |6|    |2|    |0|
			  `-'    `-'    `-'
			     `----------^

so if CPU0 gets into unqueue path of osq_lock it will keep spinning
in infinite loop as condition prev->next == node will never be true.

Signed-off-by: Prateek Sood <prsood@codeaurora.org>
[ Added pictures, rewrote comments. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sramana@codeaurora.org
Link: http://lkml.kernel.org/r/1500040076-27626-1-git-send-email-prsood@codeaurora.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
To be applied on 4.4.y as well.
Build tested on v4.4.153.

 kernel/locking/osq_lock.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index 05a37857ab55..8d7047ecef4e 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -104,6 +104,19 @@ bool osq_lock(struct optimistic_spin_queue *lock)
 
 	prev = decode_cpu(old);
 	node->prev = prev;
+
+	/*
+	 * osq_lock()			unqueue
+	 *
+	 * node->prev = prev		osq_wait_next()
+	 * WMB				MB
+	 * prev->next = node		next->prev = prev // unqueue-C
+	 *
+	 * Here 'node->prev' and 'next->prev' are the same variable and we need
+	 * to ensure these stores happen in-order to avoid corrupting the list.
+	 */
+	smp_wmb();
+
 	WRITE_ONCE(prev->next, node);
 
 	/*
-- 
2.7.4

[PATCH for-4.9.y 13/14] mm, vmscan: clear PGDAT_WRITEBACK when zone is balanced

[Amit Pundir]

From: Mel Gorman <mgorman@suse.de>

commit c2f83143f1c67d186520b72b6cefbf0aa07a34ee upstream.

Hillf Danton pointed out that since commit 1d82de618dd ("mm, vmscan:
make kswapd reclaim in terms of nodes") that PGDAT_WRITEBACK is no
longer cleared.

It was not noticed as triggering it requires pages under writeback to
cycle twice through the LRU and before kswapd gets stalled.
Historically, such issues tended to occur on small machines writing
heavily to slow storage such as a USB stick.

Once kswapd stalls, direct reclaim stalls may be higher but due to the
fact that memory pressure is required, it would not be very noticable.

Michal Hocko suggested removing the flag entirely but the conservative
fix is to restore the intended PGDAT_WRITEBACK behaviour and clear the
flag when a suitable zone is balanced.

Fixes: 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of nodes")
Link: http://lkml.kernel.org/r/20170203203222.gq7hk66yc36lpgtb@suse.de
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
 mm/vmscan.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f03ca5ab86b1..cfffef1f26a8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3123,6 +3123,7 @@ static bool zone_balanced(struct zone *zone, int order, int classzone_idx)
 	 */
 	clear_bit(PGDAT_CONGESTED, &zone->zone_pgdat->flags);
 	clear_bit(PGDAT_DIRTY, &zone->zone_pgdat->flags);
+	clear_bit(PGDAT_WRITEBACK, &zone->zone_pgdat->flags);
 
 	return true;
 }
-- 
2.7.4

[PATCH for-4.9.y 14/14] mm: remove seemingly spurious reclaimability check from laptop_mode gating

[Amit Pundir]

From: Johannes Weiner <hannes@cmpxchg.org>

commit 047d72c30eedcb953222810f1e7dcaae663aa452 upstream.

Commit 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of
nodes") allowed laptop_mode=1 to start writing not just when the
priority drops to DEF_PRIORITY - 2 but also when the node is
unreclaimable.

That appears to be a spurious change in this patch as I doubt the series
was tested with laptop_mode, and neither is that particular change
mentioned in the changelog.  Remove it, it's still recent.

Link: http://lkml.kernel.org/r/20170228214007.5621-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jia He <hejianet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index cfffef1f26a8..4e5846b8b5eb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3301,7 +3301,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 		 * If we're getting trouble reclaiming, start doing writepage
 		 * even in laptop mode.
 		 */
-		if (sc.priority < DEF_PRIORITY - 2 || !pgdat_reclaimable(pgdat))
+		if (sc.priority < DEF_PRIORITY - 2)
 			sc.may_writepage = 1;
 
 		/* Call soft limit reclaim before calling shrink_node. */
-- 
2.7.4

Re: [PATCH for-4.9.y 00/14] Few upstream fixes from OnePlus6's kernel tree

[Greg KH]

On Wed, Aug 29, 2018 at 01:43:11AM +0530, Amit Pundir wrote:
> Hi Greg,
> 
> For your consideration, few upstream fixes picked up from
> Qcom's android-4.9 BSP tree for OnePlus 6 device.
> 
> Cherry-picked and build tested for ARCH=x86_64/mips on v4.9.124.
> Few patches are applicable for 4.4.y and 3.18.y as well and
> explicitly marked so respectively.

All but the random patch are now queued up, thanks.

gre k-h