bfq_setup_cooperator() uses bfqd->in_serv_last_pos so detect whether it
makes sense to merge current bfq queue with the in-service queue.
However if the in-service queue is freshly scheduled and didn't dispatch
any requests yet, bfqd->in_serv_last_pos is stale and contains value
from the previously scheduled bfq queue which can thus result in a bogus
decision that the two queues should be merged. This bug can be observed
for example with the following fio jobfile:
[global]
direct=0
ioengine=sync
invalidate=1
size=1g
rw=read
[reader]
numjobs=4
directory=/mnt
where the 4 processes will end up in the one shared bfq queue although
they do IO to physically very distant files (for some reason I was able to
observe this only with slice_idle=1ms setting).
Fix the problem by invalidating bfqd->in_serv_last_pos when switching
in-service queue.
Fixes: 058fdecc6de7 ("block, bfq: fix in-service-queue check for queue merging")
CC: stable(a)vger.kernel.org
Signed-off-by: Jan Kara <jack(a)suse.cz>
---
block/bfq-iosched.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 3d411716d7ee..50017275915f 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2937,6 +2937,7 @@ static void __bfq_set_in_service_queue(struct bfq_data *bfqd,
}
bfqd->in_service_queue = bfqq;
+ bfqd->in_serv_last_pos = 0;
}
/*
--
2.16.4
The TLB flush optimisation (a46cc7a90f: powerpc/mm/radix: Improve TLB/PWC
flushes) may result in random memory corruption. Any concurrent page-table walk
could end up with a Use-after-Free. Even on UP this might give issues, since
mmu_gather is preemptible these days. An interrupt or preempted task accessing
user pages might stumble into the free page if the hardware caches page
directories.
The series is a backport of the fix sent by Peter [1].
The first three patches are dependencies for the last patch (avoid potential
double flush). If the performance impact due to double flush is considered
trivial then the first three patches and last patch may be dropped.
This is only for v4.19 stable.
[1] https://patchwork.kernel.org/cover/11284843/
--
Changelog:
v2: Send the patches with the correct format (commit sha1 upstream) for stable
v3: Fix compilation issue on ppc40x_defconfig and ppc44x_defconfig
--
Aneesh Kumar K.V (1):
powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case
Peter Zijlstra (4):
asm-generic/tlb: Track freeing of page-table directories in struct
mmu_gather
asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE_INVALIDATE
mm/mmu_gather: invalidate TLB correctly on batch allocation failure
and flush
asm-generic/tlb: avoid potential double flush
Will Deacon (1):
asm-generic/tlb: Track which levels of the page tables have been
cleared
arch/Kconfig | 3 -
arch/powerpc/Kconfig | 2 +-
arch/powerpc/include/asm/book3s/32/pgalloc.h | 8 --
arch/powerpc/include/asm/book3s/64/pgalloc.h | 2 -
arch/powerpc/include/asm/nohash/32/pgalloc.h | 8 --
arch/powerpc/include/asm/nohash/64/pgalloc.h | 9 +-
arch/powerpc/include/asm/tlb.h | 11 ++
arch/powerpc/mm/pgtable-book3s64.c | 7 --
arch/sparc/include/asm/tlb_64.h | 9 ++
arch/x86/Kconfig | 1 -
include/asm-generic/tlb.h | 103 ++++++++++++++++---
mm/memory.c | 20 ++--
12 files changed, 123 insertions(+), 60 deletions(-)
--
2.24.1
From: Alexander Duyck <alexander.h.duyck(a)linux.intel.com>
From: Alexander Duyck <alexander.h.duyck(a)linux.intel.com>
commit 56ec43d8b02719402c9fcf984feb52ec2300f8a5 upstream.
As best as I can tell the meminit_pfn_in_nid call is completely redundant.
The deferred memory initialization is already making use of
for_each_free_mem_range which in turn will call into __next_mem_range
which will only return a memory range if it matches the node ID provided
assuming it is not NUMA_NO_NODE.
I am operating on the assumption that there are no zones or pgdata_t
structures that have a NUMA node of NUMA_NO_NODE associated with them. If
that is the case then __next_mem_range will never return a memory range
that doesn't match the zone's node ID and as such the check is redundant.
So one piece I would like to verify on this is if this works for ia64.
Technically it was using a different approach to get the node ID, but it
seems to have the node ID also encoded into the memblock. So I am
assuming this is okay, but would like to get confirmation on that.
On my x86_64 test system with 384GB of memory per node I saw a reduction
in initialization time from 2.80s to 1.85s as a result of this patch.
Link: http://lkml.kernel.org/r/20190405221219.12227.93957.stgit@localhost.localdo…
Signed-off-by: Alexander Duyck <alexander.h.duyck(a)linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin(a)microsoft.com>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Cc: Mike Rapoport <rppt(a)linux.ibm.com>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Dave Jiang <dave.jiang(a)intel.com>
Cc: David S. Miller <davem(a)davemloft.net>
Cc: Ingo Molnar <mingo(a)kernel.org>
Cc: Khalid Aziz <khalid.aziz(a)oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov(a)linux.intel.com>
Cc: Laurent Dufour <ldufour(a)linux.vnet.ibm.com>
Cc: Matthew Wilcox <willy(a)infradead.org>
Cc: Mel Gorman <mgorman(a)techsingularity.net>
Cc: Mike Rapoport <rppt(a)linux.vnet.ibm.com>
Cc: Pavel Tatashin <pasha.tatashin(a)soleen.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: <yi.z.zhang(a)linux.intel.com>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Signed-off-by: Pavel Tatashin <pasha.tatashin(a)soleen.com>
---
mm/page_alloc.c | 51 ++++++++++++++-----------------------------------
1 file changed, 14 insertions(+), 37 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d8c3051387d1..c86a117acb5b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1321,36 +1321,22 @@ int __meminit early_pfn_to_nid(unsigned long pfn)
#endif
#ifdef CONFIG_NODES_SPAN_OTHER_NODES
-static inline bool __meminit __maybe_unused
-meminit_pfn_in_nid(unsigned long pfn, int node,
- struct mminit_pfnnid_cache *state)
+/* Only safe to use early in boot when initialisation is single-threaded */
+static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
{
int nid;
- nid = __early_pfn_to_nid(pfn, state);
+ nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
if (nid >= 0 && nid != node)
return false;
return true;
}
-/* Only safe to use early in boot when initialisation is single-threaded */
-static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
-{
- return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache);
-}
-
#else
-
static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
{
return true;
}
-static inline bool __meminit __maybe_unused
-meminit_pfn_in_nid(unsigned long pfn, int node,
- struct mminit_pfnnid_cache *state)
-{
- return true;
-}
#endif
@@ -1480,21 +1466,13 @@ static inline void __init pgdat_init_report_one_done(void)
*
* Then, we check if a current large page is valid by only checking the validity
* of the head pfn.
- *
- * Finally, meminit_pfn_in_nid is checked on systems where pfns can interleave
- * within a node: a pfn is between start and end of a node, but does not belong
- * to this memory node.
*/
-static inline bool __init
-deferred_pfn_valid(int nid, unsigned long pfn,
- struct mminit_pfnnid_cache *nid_init_state)
+static inline bool __init deferred_pfn_valid(unsigned long pfn)
{
if (!pfn_valid_within(pfn))
return false;
if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
return false;
- if (!meminit_pfn_in_nid(pfn, nid, nid_init_state))
- return false;
return true;
}
@@ -1502,15 +1480,14 @@ deferred_pfn_valid(int nid, unsigned long pfn,
* Free pages to buddy allocator. Try to free aligned pages in
* pageblock_nr_pages sizes.
*/
-static void __init deferred_free_pages(int nid, int zid, unsigned long pfn,
+static void __init deferred_free_pages(unsigned long pfn,
unsigned long end_pfn)
{
- struct mminit_pfnnid_cache nid_init_state = { };
unsigned long nr_pgmask = pageblock_nr_pages - 1;
unsigned long nr_free = 0;
for (; pfn < end_pfn; pfn++) {
- if (!deferred_pfn_valid(nid, pfn, &nid_init_state)) {
+ if (!deferred_pfn_valid(pfn)) {
deferred_free_range(pfn - nr_free, nr_free);
nr_free = 0;
} else if (!(pfn & nr_pgmask)) {
@@ -1530,17 +1507,18 @@ static void __init deferred_free_pages(int nid, int zid, unsigned long pfn,
* by performing it only once every pageblock_nr_pages.
* Return number of pages initialized.
*/
-static unsigned long __init deferred_init_pages(int nid, int zid,
+static unsigned long __init deferred_init_pages(struct zone *zone,
unsigned long pfn,
unsigned long end_pfn)
{
- struct mminit_pfnnid_cache nid_init_state = { };
unsigned long nr_pgmask = pageblock_nr_pages - 1;
+ int nid = zone_to_nid(zone);
unsigned long nr_pages = 0;
+ int zid = zone_idx(zone);
struct page *page = NULL;
for (; pfn < end_pfn; pfn++) {
- if (!deferred_pfn_valid(nid, pfn, &nid_init_state)) {
+ if (!deferred_pfn_valid(pfn)) {
page = NULL;
continue;
} else if (!page || !(pfn & nr_pgmask)) {
@@ -1603,12 +1581,12 @@ static int __init deferred_init_memmap(void *data)
for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
epfn = min_t(unsigned long, zone_end_pfn(zone), PFN_DOWN(epa));
- nr_pages += deferred_init_pages(nid, zid, spfn, epfn);
+ nr_pages += deferred_init_pages(zone, spfn, epfn);
}
for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
epfn = min_t(unsigned long, zone_end_pfn(zone), PFN_DOWN(epa));
- deferred_free_pages(nid, zid, spfn, epfn);
+ deferred_free_pages(spfn, epfn);
}
pgdat_resize_unlock(pgdat, &flags);
@@ -1640,7 +1618,6 @@ static int __init deferred_init_memmap(void *data)
static noinline bool __init
deferred_grow_zone(struct zone *zone, unsigned int order)
{
- int zid = zone_idx(zone);
int nid = zone_to_nid(zone);
pg_data_t *pgdat = NODE_DATA(nid);
unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
@@ -1690,7 +1667,7 @@ deferred_grow_zone(struct zone *zone, unsigned int order)
while (spfn < epfn && nr_pages < nr_pages_needed) {
t = ALIGN(spfn + PAGES_PER_SECTION, PAGES_PER_SECTION);
first_deferred_pfn = min(t, epfn);
- nr_pages += deferred_init_pages(nid, zid, spfn,
+ nr_pages += deferred_init_pages(zone, spfn,
first_deferred_pfn);
spfn = first_deferred_pfn;
}
@@ -1702,7 +1679,7 @@ deferred_grow_zone(struct zone *zone, unsigned int order)
for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
epfn = min_t(unsigned long, first_deferred_pfn, PFN_DOWN(epa));
- deferred_free_pages(nid, zid, spfn, epfn);
+ deferred_free_pages(spfn, epfn);
if (first_deferred_pfn == epfn)
break;
--
2.25.1
This is the start of the stable review cycle for the 5.2.6 release.
There are 20 patches in this series, all will be posted as a response
to this one. If anyone has any issues with these being applied, please
let me know.
Responses should be made by Sun 04 Aug 2019 09:19:34 AM UTC.
Anything received after that time might be too late.
The whole patch series can be found in one patch at:
https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.2.6-rc1.…
or in the git tree and branch at:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.2.y
and the diffstat can be found below.
thanks,
greg k-h
-------------
Pseudo-Shortlog of commits:
Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Linux 5.2.6-rc1
Yan, Zheng <zyan(a)redhat.com>
ceph: hold i_ceph_lock when removing caps for freeing inode
Yoshinori Sato <ysato(a)users.sourceforge.jp>
Fix allyesconfig output.
Miroslav Lichvar <mlichvar(a)redhat.com>
drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl
Linus Torvalds <torvalds(a)linux-foundation.org>
/proc/<pid>/cmdline: add back the setproctitle() special case
Linus Torvalds <torvalds(a)linux-foundation.org>
/proc/<pid>/cmdline: remove all the special cases
Jann Horn <jannh(a)google.com>
sched/fair: Use RCU accessors consistently for ->numa_group
Jann Horn <jannh(a)google.com>
sched/fair: Don't free p->numa_faults with concurrent readers
Vladis Dronov <vdronov(a)redhat.com>
Bluetooth: hci_uart: check for missing tty operations
Marta Rybczynska <mrybczyn(a)kalray.eu>
nvme: fix multipath crash when ANA is deactivated
Florian Westphal <fw(a)strlen.de>
xfrm: policy: fix bydst hlist corruption on hash rebuild
Luke Nowakowski-Krijger <lnowakow(a)eng.ucsd.edu>
media: radio-raremono: change devm_k*alloc to k*alloc
Benjamin Coddington <bcodding(a)redhat.com>
NFS: Cleanup if nfs_match_client is interrupted
Andrey Konovalov <andreyknvl(a)google.com>
media: pvrusb2: use a different format for warnings
Oliver Neukum <oneukum(a)suse.com>
media: cpia2_usb: first wake up, then free in disconnect
Fabio Estevam <festevam(a)gmail.com>
ath10k: Change the warning message string
Sean Young <sean(a)mess.org>
media: au0828: fix null dereference in error path
Stanislav Fomichev <sdf(a)google.com>
bpf: fix NULL deref in btf_type_is_resolve_source_only
Takashi Iwai <tiwai(a)suse.de>
ALSA: usb-audio: Sanity checks for each pipe and EP types
Phong Tran <tranmanphong(a)gmail.com>
ISDN: hfcsusb: checking idx of ep configuration
Sunil Muthuswamy <sunilmut(a)microsoft.com>
vsock: correct removal of socket from the list
-------------
Diffstat:
Makefile | 4 +-
arch/sh/boards/Kconfig | 14 +--
drivers/bluetooth/hci_ath.c | 3 +
drivers/bluetooth/hci_bcm.c | 3 +
drivers/bluetooth/hci_intel.c | 3 +
drivers/bluetooth/hci_ldisc.c | 13 +++
drivers/bluetooth/hci_mrvl.c | 3 +
drivers/bluetooth/hci_qca.c | 3 +
drivers/bluetooth/hci_uart.h | 1 +
drivers/isdn/hardware/mISDN/hfcsusb.c | 3 +
drivers/media/radio/radio-raremono.c | 30 ++++--
drivers/media/usb/au0828/au0828-core.c | 12 +--
drivers/media/usb/cpia2/cpia2_usb.c | 3 +-
drivers/media/usb/pvrusb2/pvrusb2-hdw.c | 4 +-
drivers/media/usb/pvrusb2/pvrusb2-i2c-core.c | 6 +-
drivers/media/usb/pvrusb2/pvrusb2-std.c | 2 +-
drivers/net/wireless/ath/ath10k/usb.c | 2 +-
drivers/nvme/host/multipath.c | 8 +-
drivers/nvme/host/nvme.h | 6 +-
drivers/pps/pps.c | 8 ++
fs/ceph/caps.c | 10 +-
fs/ceph/inode.c | 2 +-
fs/ceph/super.h | 2 +-
fs/exec.c | 2 +-
fs/nfs/client.c | 4 +-
fs/proc/base.c | 132 +++++++++++++-----------
include/linux/sched.h | 10 +-
include/linux/sched/numa_balancing.h | 4 +-
kernel/bpf/btf.c | 12 +--
kernel/fork.c | 2 +-
kernel/sched/fair.c | 144 +++++++++++++++++++--------
net/vmw_vsock/af_vsock.c | 38 ++-----
net/xfrm/xfrm_policy.c | 12 ++-
sound/usb/helper.c | 17 ++++
sound/usb/helper.h | 1 +
sound/usb/quirks.c | 18 +++-
tools/testing/selftests/net/xfrm_policy.sh | 27 ++++-
37 files changed, 368 insertions(+), 200 deletions(-)
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 39f23ce07b9355d05a64ae303ce20d1c4b92b957 Mon Sep 17 00:00:00 2001
From: Vincent Guittot <vincent.guittot(a)linaro.org>
Date: Wed, 13 May 2020 15:55:28 +0200
Subject: [PATCH] sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list
Although not exactly identical, unthrottle_cfs_rq() and enqueue_task_fair()
are quite close and follow the same sequence for enqueuing an entity in the
cfs hierarchy. Modify unthrottle_cfs_rq() to use the same pattern as
enqueue_task_fair(). This fixes a problem already faced with the latter and
add an optimization in the last for_each_sched_entity loop.
Fixes: fe61468b2cb (sched/fair: Fix enqueue_task_fair warning)
Reported-by Tao Zhou <zohooouoto(a)zoho.com.cn>
Signed-off-by: Vincent Guittot <vincent.guittot(a)linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Reviewed-by: Phil Auld <pauld(a)redhat.com>
Reviewed-by: Ben Segall <bsegall(a)google.com>
Link: https://lkml.kernel.org/r/20200513135528.4742-1-vincent.guittot@linaro.org
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c6d57c334d51..538ba5d94e99 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4774,7 +4774,6 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
struct rq *rq = rq_of(cfs_rq);
struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
struct sched_entity *se;
- int enqueue = 1;
long task_delta, idle_task_delta;
se = cfs_rq->tg->se[cpu_of(rq)];
@@ -4798,26 +4797,44 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
idle_task_delta = cfs_rq->idle_h_nr_running;
for_each_sched_entity(se) {
if (se->on_rq)
- enqueue = 0;
+ break;
+ cfs_rq = cfs_rq_of(se);
+ enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
+ cfs_rq->h_nr_running += task_delta;
+ cfs_rq->idle_h_nr_running += idle_task_delta;
+
+ /* end evaluation on encountering a throttled cfs_rq */
+ if (cfs_rq_throttled(cfs_rq))
+ goto unthrottle_throttle;
+ }
+
+ for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
- if (enqueue) {
- enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
- } else {
- update_load_avg(cfs_rq, se, 0);
- se_update_runnable(se);
- }
+
+ update_load_avg(cfs_rq, se, UPDATE_TG);
+ se_update_runnable(se);
cfs_rq->h_nr_running += task_delta;
cfs_rq->idle_h_nr_running += idle_task_delta;
+
+ /* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(cfs_rq))
- break;
+ goto unthrottle_throttle;
+
+ /*
+ * One parent has been throttled and cfs_rq removed from the
+ * list. Add it back to not break the leaf list.
+ */
+ if (throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
}
- if (!se)
- add_nr_running(rq, task_delta);
+ /* At this point se is NULL and we are at root level*/
+ add_nr_running(rq, task_delta);
+unthrottle_throttle:
/*
* The cfs_rq_throttled() breaks in the above iteration can result in
* incomplete leaf list maintenance, resulting in triggering the
@@ -4826,7 +4843,8 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
- list_add_leaf_cfs_rq(cfs_rq);
+ if (list_add_leaf_cfs_rq(cfs_rq))
+ break;
}
assert_list_leaf_cfs_rq(rq);
In commit d8bb6718c4db ("arm64: Make debug exception handlers visible
from RCU") debug_exception_enter and exit were added to deal with better
tracking of RCU state - however, in addition to that, but not mentioned
in the commit log, a preempt_disable/enable pair were also added.
Based on the comment (being removed here) it would seem that the pair
were not added to address a specific problem, but just as a proactive,
preventative measure - as in "seemed like a good idea at the time".
The problem is that do_debug_exception() eventually calls out to
generic kernel code like do_force_sig_info() which takes non-raw locks
and on -rt enabled kernels, results in things looking like the following,
since on -rt kernels, it is noticed that preemption is still disabled.
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:975
in_atomic(): 1, irqs_disabled(): 0, pid: 35658, name: gdbtest
Preemption disabled at:
[<ffff000010081578>] do_debug_exception+0x38/0x1a4
Call trace:
dump_backtrace+0x0/0x138
show_stack+0x24/0x30
dump_stack+0x94/0xbc
___might_sleep+0x13c/0x168
rt_spin_lock+0x40/0x80
do_force_sig_info+0x30/0xe0
force_sig_fault+0x64/0x90
arm64_force_sig_fault+0x50/0x80
send_user_sigtrap+0x50/0x80
brk_handler+0x98/0xc8
do_debug_exception+0x70/0x1a4
el0_dbg+0x18/0x20
The reproducer was basically an automated gdb test that set a breakpoint
on a simple "hello world" program and then quit gdb once the breakpoint
was hit - i.e. "(gdb) A debugging session is active. Quit anyway? "
Fixes: d8bb6718c4db ("arm64: Make debug exception handlers visible from RCU")
Cc: stable(a)vger.kernel.org
Cc: Naresh Kamboju <naresh.kamboju(a)linaro.org>
Cc: Paul E. McKenney <paulmck(a)linux.ibm.com>
Cc: Masami Hiramatsu <mhiramat(a)kernel.org>
Cc: Will Deacon <will(a)kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker(a)windriver.com>
---
arch/arm64/mm/fault.c | 11 -----------
1 file changed, 11 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 8afb238ff335..4d83ec991b33 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -788,13 +788,6 @@ void __init hook_debug_fault_code(int nr,
debug_fault_info[nr].name = name;
}
-/*
- * In debug exception context, we explicitly disable preemption despite
- * having interrupts disabled.
- * This serves two purposes: it makes it much less likely that we would
- * accidentally schedule in exception context and it will force a warning
- * if we somehow manage to schedule by accident.
- */
static void debug_exception_enter(struct pt_regs *regs)
{
/*
@@ -816,8 +809,6 @@ static void debug_exception_enter(struct pt_regs *regs)
rcu_nmi_enter();
}
- preempt_disable();
-
/* This code is a bit fragile. Test it. */
RCU_LOCKDEP_WARN(!rcu_is_watching(), "exception_enter didn't work");
}
@@ -825,8 +816,6 @@ NOKPROBE_SYMBOL(debug_exception_enter);
static void debug_exception_exit(struct pt_regs *regs)
{
- preempt_enable_no_resched();
-
if (!user_mode(regs))
rcu_nmi_exit();
--
2.7.4