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Fix script loading synchronization issue and add LuaUnpack submodule - #1

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Fix script loading synchronization issue and add LuaUnpack submodule#1
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Comment threadnet/core/dev.c Outdated
#ifdef CONFIG_XDP_LUA
xdplua->L = luaL_newstate();
if (!xdplua->L) {
kfree(xdplua);

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Leaving xdplua dangling.
Also would be weird being in a state where possibly some CPUs managed to get a lua_State, others did not.
Maybe it would make more sense to BUG_ON here.

Comment threadinclude/net/xdp.h Outdated
#ifdef CONFIG_XDP_LUA
struct xdplua {
struct lua_State *L;
spinlock_t *lock;

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Is spinlock the right concurrency primitive here?
So this is a lock per lua state, and there is a lua state per CPU, and spinlocks are only appropriate for locking accesses between different CPUs to the same data. And also, even in that context, spinlocks are highly inefficient when they are taken for a long time, such as would be the case for executing a lua script.

So if you ever happened upon a case where the same CPU got this lock multiple times, it would have hung forever, so I suspect that you might not even need a lock at all.

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Unfortunately a lock is indeed needed. If a user attempts to load a Lua script while another script is being executed in the same Lua state, we will have concurrent accesses to the a Lua State, which will cause synchronization issues. If not a spinlock, what would you suggest?

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Based on your other message, I see now that what you probably need is just local_bh_disable and local_bh_enable when loading script.

Comment threadinclude/net/xdp.h Outdated
Comment on lines +67 to +70
struct xdplua {
struct lua_State *L;
spinlock_t *lock;
};

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So this struct xdplua is creating another unnecessary level of indirection.
so you already have this:

static DEFINE_PER_CPU(spinlock_t, lua_state_lock);

And you can easily grab this, as you already do:

xdplua->lock = per_cpu_ptr(&lua_state_lock, i);

This might be moot if you just remove the lock anyway.

Also, should be possible, and it would be much superior, if instead of having a lua_State pointer as the per cpu attribute, you just had the value directly, that would be one less unnecessary level of indirection.

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Yes, maybe it would be possible not to use this struct. I'll try this out.

@VictorNogueiraRioVictorNogueiraRio changed the title Vnogueira 1Fix script loading synchronization issue and add LuaUnpack submoduleFeb 21, 2020
@lneto
lneto requested a review from iru-February 22, 2020 20:04
VictorNogueiraRio pushed a commit that referenced this pull request May 30, 2020
The dpio irqs must be registered when you can actually
receive interrupts, ie when the dpios are created.
Kernel goes through NULL pointer dereference errors
followed by kernel panic [1] because the dpio irqs are
enabled before the dpio is created.
[1]
Unable to handle kernel NULL pointer dereference at virtual address 0040
fsl_mc_dpio dpio.14: probed
fsl_mc_dpio dpio.13: Adding to iommu group 11
ISV = 0, ISS = 0x00000004
Unable to handle kernel NULL pointer dereference at virtual address 0040
Mem abort info:
ESR = 0x96000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
[0000000000000040] user address but active_mm is swapper
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 2 PID: 151 Comm: kworker/2:1 Not tainted 5.6.0-rc4-next-20200304 #1
Hardware name: NXP Layerscape LX2160ARDB (DT)
Workqueue: events deferred_probe_work_func
pstate: 00000085 (nzcv daIf -PAN -UAO)
pc : dpaa2_io_irq+0x18/0xe0
lr : dpio_irq_handler+0x1c/0x28
sp : ffff800010013e20
x29: ffff800010013e20 x28: ffff0026d9b4c140
x27: ffffa1d38a142018 x26: ffff0026d2953400
x25: ffffa1d38a142018 x24: ffffa1d38a7ba1d8
x23: ffff800010013f24 x22: 0000000000000000
x21: 0000000000000072 x20: ffff0026d2953400
x19: ffff0026d2a68b80 x18: 0000000000000001
x17: 000000002fb37f3d x16: 0000000035eafadd
x15: ffff0026d9b4c5b8 x14: ffffffffffffffff
x13: ff00000000000000 x12: 0000000000000038
x11: 0101010101010101 x10: 0000000000000040
x9 : ffffa1d388db11e4 x8 : ffffa1d38a7e40f0
x7 : ffff0026da414f38 x6 : 0000000000000000
x5 : ffff0026da414d80 x4 : ffff5e5353d0c000
x3 : ffff800010013f60 x2 : ffffa1d388db11c8
x1 : ffff0026d2a67c00 x0 : 0000000000000000
Call trace:
dpaa2_io_irq+0x18/0xe0
dpio_irq_handler+0x1c/0x28
__handle_irq_event_percpu+0x78/0x2c0
handle_irq_event_percpu+0x38/0x90
handle_irq_event+0x4c/0xd0
handle_fasteoi_irq+0xbc/0x168
generic_handle_irq+0x2c/0x40
__handle_domain_irq+0x68/0xc0
gic_handle_irq+0x64/0x150
el1_irq+0xb8/0x180
_raw_spin_unlock_irqrestore+0x14/0x48
irq_set_affinity_hint+0x6c/0xa0
dpaa2_dpio_probe+0x2a4/0x518
fsl_mc_driver_probe+0x28/0x70
really_probe+0xdc/0x320
driver_probe_device+0x5c/0xf0
__device_attach_driver+0x88/0xc0
bus_for_each_drv+0x7c/0xc8
__device_attach+0xe4/0x140
device_initial_probe+0x18/0x20
bus_probe_device+0x98/0xa0
device_add+0x41c/0x758
fsl_mc_device_add+0x184/0x530
dprc_scan_objects+0x280/0x370
dprc_probe+0x124/0x3b0
fsl_mc_driver_probe+0x28/0x70
really_probe+0xdc/0x320
driver_probe_device+0x5c/0xf0
__device_attach_driver+0x88/0xc0
bus_for_each_drv+0x7c/0xc8
__device_attach+0xe4/0x140
device_initial_probe+0x18/0x20
bus_probe_device+0x98/0xa0
deferred_probe_work_func+0x74/0xa8
process_one_work+0x1c8/0x470
worker_thread+0x1f8/0x428
kthread+0x124/0x128
ret_from_fork+0x10/0x18
Code: a9bc7bfd 910003fd a9025bf5 a90363f7 (f9402015)
---[ end trace 38298e1a29e7a570 ]---
Kernel panic - not syncing: Fatal exception in interrupt
SMP: stopping secondary CPUs
Mem abort info:
ESR = 0x96000004
CM = 0, WnR = 0
EC = 0x25: DABT (current EL), IL = 32 bits
[0000000000000040] user address but active_mm is swapper
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
[0000000000000040] user address but active_mm is swapper
SMP: failed to stop secondary CPUs 0-2
Kernel Offset: 0x21d378600000 from 0xffff800010000000
PHYS_OFFSET: 0xffffe92180000000
CPU features: 0x10002,21806008
Memory Limit: none
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Grigore Popescu <grigore.popescu@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
VictorNogueiraRio pushed a commit that referenced this pull request May 30, 2020
It might have the unaligned access exception when trying to exchange data
with user space program. In this case, it failed in tty_ioctl(). Therefore
we should enable uaccess.S for NOMMU mode since the generic code doesn't
handle the unaligned access cases.
0x8013a212 <tty_ioctl+462>: ld a5,460(s1)
[ 0.115279] Oops - load address misaligned [#1]
[ 0.115284] CPU: 0 PID: 29 Comm: sh Not tainted 5.4.0-rc5-00020-gb4c27160d562-dirty #36
[ 0.115294] epc: 000000008013a212 ra : 000000008013a212 sp : 000000008f48dd50
[ 0.115303] gp : 00000000801cac28 tp : 000000008fb80000 t0 : 00000000000000e8
[ 0.115312] t1 : 000000008f58f108 t2 : 0000000000000009 s0 : 000000008f48ddf0
[ 0.115321] s1 : 000000008f8c6220 a0 : 0000000000000001 a1 : 000000008f48dd28
[ 0.115330] a2 : 000000008fb80000 a3 : 00000000801a7398 a4 : 0000000000000000
[ 0.115339] a5 : 0000000000000000 a6 : 000000008f58f0c6 a7 : 000000000000001d
[ 0.115348] s2 : 000000008f8c6308 s3 : 000000008f78b7c8 s4 : 000000008fb834c0
[ 0.115357] s5 : 0000000000005413 s6 : 0000000000000000 s7 : 000000008f58f2b0
[ 0.115366] s8 : 000000008f858008 s9 : 000000008f776818 s10: 000000008f776830
[ 0.115375] s11: 000000008fb840a8 t3 : 1999999999999999 t4 : 000000008f78704c
[ 0.115384] t5 : 0000000000000005 t6 : 0000000000000002
[ 0.115391] status: 0000000200001880 badaddr: 000000008f8c63ec cause: 0000000000000004
[ 0.115401] ---[ end trace 00d490c6a8b6c9ac ]---
This failure could be fixed after this patch applied.
[ 0.002282] Run /init as init process
Initializing random number generator... [ 0.005573] random: dd: uninitialized urandom read (512 bytes read)
done.
Welcome to Buildroot
buildroot login: root
Password:
Jan 1 00:00:00 login[62]: root login on 'ttySIF0'
~ #
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
VictorNogueiraRio pushed a commit that referenced this pull request May 30, 2020
Fix the crash like this:
BUG: Kernel NULL pointer dereference on read at 0x00000000
Faulting instruction address: 0xc000000000c3447c
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
CPU: 11 PID: 7519 Comm: lt-ndctl Not tainted 5.6.0-rc7-autotest #1
...
NIP [c000000000c3447c] vmemmap_populated+0x98/0xc0
LR [c000000000088354] vmemmap_free+0x144/0x320
Call Trace:
section_deactivate+0x220/0x240
__remove_pages+0x118/0x170
arch_remove_memory+0x3c/0x150
memunmap_pages+0x1cc/0x2f0
devm_action_release+0x30/0x50
release_nodes+0x2f8/0x3e0
device_release_driver_internal+0x168/0x270
unbind_store+0x130/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x68/0x80
kernfs_fop_write+0x100/0x290
__vfs_write+0x3c/0x70
vfs_write+0xcc/0x240
ksys_write+0x7c/0x140
system_call+0x5c/0x68
The crash is due to NULL dereference at
test_bit(idx, ms->usage->subsection_map);
due to ms->usage = NULL in pfn_section_valid()
With commit d41e2f3 ("mm/hotplug: fix hot remove failure in
SPARSEMEM|!VMEMMAP case") section_mem_map is set to NULL after
depopulate_section_mem(). This was done so that pfn_page() can work
correctly with kernel config that disables SPARSEMEM_VMEMMAP. With that
config pfn_to_page does
__section_mem_map_addr(__sec) + __pfn;
where
static inline struct page *__section_mem_map_addr(struct mem_section *section)
{
unsigned long map = section->section_mem_map;
map &= SECTION_MAP_MASK;
return (struct page *)map;
}
Now with SPASEMEM_VMEMAP enabled, mem_section->usage->subsection_map is
used to check the pfn validity (pfn_valid()). Since section_deactivate
release mem_section->usage if a section is fully deactivated,
pfn_valid() check after a subsection_deactivate cause a kernel crash.
static inline int pfn_valid(unsigned long pfn)
{
...
return early_section(ms) || pfn_section_valid(ms, pfn);
}
where
static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
{
int idx = subsection_map_index(pfn);
return test_bit(idx, ms->usage->subsection_map);
}
Avoid this by clearing SECTION_HAS_MEM_MAP when mem_section->usage is
freed. For architectures like ppc64 where large pages are used for
vmmemap mapping (16MB), a specific vmemmap mapping can cover multiple
sections. Hence before a vmemmap mapping page can be freed, the kernel
needs to make sure there are no valid sections within that mapping.
Clearing the section valid bit before depopulate_section_memap enables
this.
[aneesh.kumar@linux.ibm.com: add comment]
Link: http://lkml.kernel.org/r/20200326133235.343616-1-aneesh.kumar@linux.ibm.comLink: http://lkml.kernel.org/r/20200325031914.107660-1-aneesh.kumar@linux.ibm.com
Fixes: d41e2f3 ("mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit e0f1a30 ]
When, at probe time, an SCMI communication failure inhibits the capacity
to query power domains states, such domains should be skipped.
Registering partially initialized SCMI power domains with genpd will
causes kernel panic.
arm-scmi timed out in resp(caller: scmi_power_state_get+0xa4/0xd0)
scmi-power-domain scmi_dev.2: failed to get state for domain 9
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=00000009f3691000
[0000000000000000] pgd=00000009f1ca0003, p4d=00000009f1ca0003, pud=00000009f35ea003, pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
CPU: 2 PID: 381 Comm: bash Not tainted 5.8.0-rc1-00011-gebd118c2cca8 #2
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Jan 3 2020
Internal error: Oops: 96000006 [#1] PREEMPT SMP
pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--)
pc : of_genpd_add_provider_onecell+0x98/0x1f8
lr : of_genpd_add_provider_onecell+0x48/0x1f8
Call trace:
of_genpd_add_provider_onecell+0x98/0x1f8
scmi_pm_domain_probe+0x174/0x1e8
scmi_dev_probe+0x90/0xe0
really_probe+0xe4/0x448
driver_probe_device+0xfc/0x168
device_driver_attach+0x7c/0x88
bind_store+0xe8/0x128
drv_attr_store+0x2c/0x40
sysfs_kf_write+0x4c/0x60
kernfs_fop_write+0x114/0x230
__vfs_write+0x24/0x50
vfs_write+0xbc/0x1e0
ksys_write+0x70/0xf8
__arm64_sys_write+0x24/0x30
el0_svc_common.constprop.3+0x94/0x160
do_el0_svc+0x2c/0x98
el0_sync_handler+0x148/0x1a8
el0_sync+0x158/0x180
Do not register any power domain that failed to be queried with genpd.
Fixes: 898216c ("firmware: arm_scmi: add device power domain support using genpd")
Link: https://lore.kernel.org/r/20200619220330.12217-1-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit 60f80d6 ]
reproduction steps:
```
node1 # mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda
/dev/sdb
node2 # mdadm -A /dev/md0 /dev/sda /dev/sdb
node1 # mdadm -G /dev/md0 -b none
mdadm: failed to remove clustered bitmap.
node1 # mdadm -S --scan
^C <==== mdadm hung & kernel crash
```
kernel stack:
```
[ 335.230657] general protection fault: 0000 [#1] SMP NOPTI
[...]
[ 335.230848] Call Trace:
[ 335.230873] ? unlock_all_bitmaps+0x5/0x70 [md_cluster]
[ 335.230886] unlock_all_bitmaps+0x3d/0x70 [md_cluster]
[ 335.230899] leave+0x10f/0x190 [md_cluster]
[ 335.230932] ? md_super_wait+0x93/0xa0 [md_mod]
[ 335.230947] ? leave+0x5/0x190 [md_cluster]
[ 335.230973] md_cluster_stop+0x1a/0x30 [md_mod]
[ 335.230999] md_bitmap_free+0x142/0x150 [md_mod]
[ 335.231013] ? _cond_resched+0x15/0x40
[ 335.231025] ? mutex_lock+0xe/0x30
[ 335.231056] __md_stop+0x1c/0xa0 [md_mod]
[ 335.231083] do_md_stop+0x160/0x580 [md_mod]
[ 335.231119] ? 0xffffffffc05fb078
[ 335.231148] md_ioctl+0xa04/0x1930 [md_mod]
[ 335.231165] ? filename_lookup+0xf2/0x190
[ 335.231179] blkdev_ioctl+0x93c/0xa10
[ 335.231205] ? _cond_resched+0x15/0x40
[ 335.231214] ? __check_object_size+0xd4/0x1a0
[ 335.231224] block_ioctl+0x39/0x40
[ 335.231243] do_vfs_ioctl+0xa0/0x680
[ 335.231253] ksys_ioctl+0x70/0x80
[ 335.231261] __x64_sys_ioctl+0x16/0x20
[ 335.231271] do_syscall_64+0x65/0x1f0
[ 335.231278] entry_SYSCALL_64_after_hwframe+0x44/0xa9
```
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit 6eeb997 ]
This driver may take a regular spinlock when a raw spinlock
(irq_desc->lock) is already taken which results in the following
lockdep splat:
=============================
[ BUG: Invalid wait context ]
5.7.0-rc7 #1 Not tainted
-----------------------------
swapper/0/0 is trying to lock:
ffffff800303b798 (&chip_data->lock){....}-{3:3}, at: mtk_sysirq_set_type+0x48/0xc0
other info that might help us debug this:
context-{5:5}
2 locks held by swapper/0/0:
#0: ffffff800302ee68 (&desc->request_mutex){....}-{4:4}, at: __setup_irq+0xc4/0x8a0
#1: ffffff800302ecf0 (&irq_desc_lock_class){....}-{2:2}, at: __setup_irq+0xe4/0x8a0
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-rc7 #1
Hardware name: Pumpkin MT8516 (DT)
Call trace:
dump_backtrace+0x0/0x180
show_stack+0x14/0x20
dump_stack+0xd0/0x118
__lock_acquire+0x8c8/0x2270
lock_acquire+0xf8/0x470
_raw_spin_lock_irqsave+0x50/0x78
mtk_sysirq_set_type+0x48/0xc0
__irq_set_trigger+0x58/0x170
__setup_irq+0x420/0x8a0
request_threaded_irq+0xd8/0x190
timer_of_init+0x1e8/0x2c4
mtk_gpt_init+0x5c/0x1dc
timer_probe+0x74/0xf4
time_init+0x14/0x44
start_kernel+0x394/0x4f0
Replace the spinlock_t with raw_spinlock_t to avoid this warning.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200615074445.3579-1-brgl@bgdev.pl
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit 0a3b3c2 ]
A large process running on a heavily loaded system can encounter the
following RCU CPU stall warning:
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 3-....: (20998 ticks this GP) idle=4ea/1/0x4000000000000002 softirq=556558/556558 fqs=5190
(t=21013 jiffies g=1005461 q=132576)
NMI backtrace for cpu 3
CPU: 3 PID: 501900 Comm: aio-free-ring-w Kdump: loaded Not tainted 5.2.9-108_fbk12_rc3_3858_gb83b75af7909 #1
Hardware name: Wiwynn HoneyBadger/PantherPlus, BIOS HBM6.71 02/03/2016
Call Trace:
<IRQ>
dump_stack+0x46/0x60
nmi_cpu_backtrace.cold.3+0x13/0x50
? lapic_can_unplug_cpu.cold.27+0x34/0x34
nmi_trigger_cpumask_backtrace+0xba/0xca
rcu_dump_cpu_stacks+0x99/0xc7
rcu_sched_clock_irq.cold.87+0x1aa/0x397
? tick_sched_do_timer+0x60/0x60
update_process_times+0x28/0x60
tick_sched_timer+0x37/0x70
__hrtimer_run_queues+0xfe/0x270
hrtimer_interrupt+0xf4/0x210
smp_apic_timer_interrupt+0x5e/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:kmem_cache_free+0x223/0x300
Code: 88 00 00 00 0f 85 ca 00 00 00 41 8b 55 18 31 f6 f7 da 41 f6 45 0a 02 40 0f 94 c6 83 c6 05 9c 41 5e fa e8 a0 a7 01 00 41 56 9d <49> 8b 47 08 a8 03 0f 85 87 00 00 00 65 48 ff 08 e9 3d fe ff ff 65
RSP: 0018:ffffc9000e8e3da8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000020000 RBX: ffff88861b9de960 RCX: 0000000000000030
RDX: fffffffffffe41e8 RSI: 000060777fe3a100 RDI: 000000000001be18
RBP: ffffea00186e7780 R08: ffffffffffffffff R09: ffffffffffffffff
R10: ffff88861b9dea28 R11: ffff88887ffde000 R12: ffffffff81230a1f
R13: ffff888854684dc0 R14: 0000000000000206 R15: ffff8888547dbc00
? remove_vma+0x4f/0x60
remove_vma+0x4f/0x60
exit_mmap+0xd6/0x160
mmput+0x4a/0x110
do_exit+0x278/0xae0
? syscall_trace_enter+0x1d3/0x2b0
? handle_mm_fault+0xaa/0x1c0
do_group_exit+0x3a/0xa0
__x64_sys_exit_group+0x14/0x20
do_syscall_64+0x42/0x100
entry_SYSCALL_64_after_hwframe+0x44/0xa9
And on a PREEMPT=n kernel, the "while (vma)" loop in exit_mmap() can run
for a very long time given a large process. This commit therefore adds
a cond_resched() to this loop, providing RCU any needed quiescent states.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit 33a06f1 ]
When gadget registration fails, one should not call usb_del_gadget_udc().
Ensure this by setting gadget->udc to NULL. Also in case of a failure
there is no need to disable low-level hardware, so return immiedetly
instead of jumping to error_init label.
This fixes the following kernel NULL ptr dereference on gadget failure
(can be easily triggered with g_mass_storage without any module
parameters):
dwc2 12480000.hsotg: dwc2_check_params: Invalid parameter besl=1
dwc2 12480000.hsotg: dwc2_check_params: Invalid parameter g_np_tx_fifo_size=1024
dwc2 12480000.hsotg: EPs: 16, dedicated fifos, 7808 entries in SPRAM
Mass Storage Function, version: 2009/09/11
LUN: removable file: (no medium)
no file given for LUN0
g_mass_storage 12480000.hsotg: failed to start g_mass_storage: -22
8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 00000104
pgd = (ptrval)
[00000104] *pgd=00000000
Internal error: Oops: 805 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.8.0-rc5 #3133
Hardware name: Samsung Exynos (Flattened Device Tree)
Workqueue: events deferred_probe_work_func
PC is at usb_del_gadget_udc+0x38/0xc4
LR is at __mutex_lock+0x31c/0xb18
...
Process kworker/0:1 (pid: 12, stack limit = 0x(ptrval))
Stack: (0xef121db0 to 0xef122000)
...
[<c076bf3c>] (usb_del_gadget_udc) from [<c0726bec>] (dwc2_hsotg_remove+0x10/0x20)
[<c0726bec>] (dwc2_hsotg_remove) from [<c0711208>] (dwc2_driver_probe+0x57c/0x69c)
[<c0711208>] (dwc2_driver_probe) from [<c06247c0>] (platform_drv_probe+0x6c/0xa4)
[<c06247c0>] (platform_drv_probe) from [<c0621df4>] (really_probe+0x200/0x48c)
[<c0621df4>] (really_probe) from [<c06221e8>] (driver_probe_device+0x78/0x1fc)
[<c06221e8>] (driver_probe_device) from [<c061fcd4>] (bus_for_each_drv+0x74/0xb8)
[<c061fcd4>] (bus_for_each_drv) from [<c0621b54>] (__device_attach+0xd4/0x16c)
[<c0621b54>] (__device_attach) from [<c0620c98>] (bus_probe_device+0x88/0x90)
[<c0620c98>] (bus_probe_device) from [<c06211b0>] (deferred_probe_work_func+0x3c/0xd0)
[<c06211b0>] (deferred_probe_work_func) from [<c0149280>] (process_one_work+0x234/0x7dc)
[<c0149280>] (process_one_work) from [<c014986c>] (worker_thread+0x44/0x51c)
[<c014986c>] (worker_thread) from [<c0150b1c>] (kthread+0x158/0x1a0)
[<c0150b1c>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
Exception stack(0xef121fb0 to 0xef121ff8)
...
---[ end trace 9724c2fc7cc9c982 ]---
While fixing this also fix the double call to dwc2_lowlevel_hw_disable()
if dr_mode is set to USB_DR_MODE_PERIPHERAL. In such case low-level
hardware is already disabled before calling usb_add_gadget_udc(). That
function correctly preserves low-level hardware state, there is no need
for the second unconditional dwc2_lowlevel_hw_disable() call.
Fixes: 207324a ("usb: dwc2: Postponed gadget registration to the udc class driver")
Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit edd7dd2 ]
Booting Linux with a Conner CP3200 drive attached to the MESH SCSI bus
results in EH measures and a panic:
[ 25.499838] mesh: configured for synchronous 5 MB/s
[ 25.787154] mesh: performing initial bus reset...
[ 29.867115] scsi host0: MESH
[ 29.929527] mesh: target 0 synchronous at 3.6 MB/s
[ 29.998763] scsi 0:0:0:0: Direct-Access CONNER CP3200-200mb-3.5 4040 PQ: 0 ANSI: 1 CCS
[ 31.989975] sd 0:0:0:0: [sda] 415872 512-byte logical blocks: (213 MB/203 MiB)
[ 32.070975] sd 0:0:0:0: [sda] Write Protect is off
[ 32.137197] sd 0:0:0:0: [sda] Mode Sense: 5b 00 00 08
[ 32.209661] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 32.332708] sda: [mac] sda1 sda2 sda3
[ 32.417733] sd 0:0:0:0: [sda] Attached SCSI disk
... snip ...
[ 76.687067] mesh_abort((ptrval))
[ 76.743606] mesh: state at (ptrval), regs at (ptrval), dma at (ptrval)
[ 76.810798] ct=6000 seq=86 bs=4017 fc= 0 exc= 0 err= 0 im= 7 int= 0 sp=85
[ 76.880720] dma stat=84e0 cmdptr=1f73d000
[ 76.941387] phase=4 msgphase=0 conn_tgt=0 data_ptr=24576
[ 77.005567] dma_st=1 dma_ct=0 n_msgout=0
[ 77.065456] target 0: req=(ptrval) goes_out=0 saved_ptr=0
[ 77.130512] mesh_abort((ptrval))
[ 77.187670] mesh: state at (ptrval), regs at (ptrval), dma at (ptrval)
[ 77.255594] ct=6000 seq=86 bs=4017 fc= 0 exc= 0 err= 0 im= 7 int= 0 sp=85
[ 77.325778] dma stat=84e0 cmdptr=1f73d000
[ 77.387239] phase=4 msgphase=0 conn_tgt=0 data_ptr=24576
[ 77.453665] dma_st=1 dma_ct=0 n_msgout=0
[ 77.515900] target 0: req=(ptrval) goes_out=0 saved_ptr=0
[ 77.582902] mesh_host_reset
[ 88.187083] Kernel panic - not syncing: mesh: double DMA start !
[ 88.254510] CPU: 0 PID: 358 Comm: scsi_eh_0 Not tainted 5.6.13-pmac #1
[ 88.323302] Call Trace:
[ 88.378854] [e16ddc58] [c0027080] panic+0x13c/0x308 (unreliable)
[ 88.446221] [e16ddcb8] [c02b2478] mesh_start.part.12+0x130/0x414
[ 88.513298] [e16ddcf8] [c02b2fc8] mesh_queue+0x54/0x70
[ 88.577097] [e16ddd18] [c02a1848] scsi_send_eh_cmnd+0x374/0x384
[ 88.643476] [e16dddc8] [c02a1938] scsi_eh_tur+0x5c/0xb8
[ 88.707878] [e16dddf8] [c02a1ab] scsi_eh_test_devices+0x124/0x178
[ 88.775663] [e16dde28] [c02a2094] scsi_eh_ready_devs+0x588/0x8a8
[ 88.843124] [e16dde98] [c02a31d8] scsi_error_handler+0x344/0x520
[ 88.910697] [e16ddf08] [c00409c8] kthread+0xe4/0xe8
[ 88.975166] [e16ddf38] [c000f234] ret_from_kernel_thread+0x14/0x1c
[ 89.044112] Rebooting in 180 seconds..
In theory, a panic can happen after a bus or host reset with dma_started
flag set. Fix this by halting the DMA before reinitializing the host.
Don't assume that ms->current_req is set when halt_dma() is invoked as it
may not hold for bus or host reset.
BTW, this particular Conner drive can be made to work by inhibiting
disconnect/reselect with 'mesh.resel_targets=0'.
Link: https://lore.kernel.org/r/3952bc691e150a7128b29120999b6092071b039a.1595460351.git.fthain@telegraphics.com.au
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: Paul Mackerras <paulus@ozlabs.org>
Reported-and-tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
commit 18c850f upstream.
There's long existed a lockdep splat because we open our bdev's under
the ->device_list_mutex at mount time, which acquires the bd_mutex.
Usually this goes unnoticed, but if you do loopback devices at all
suddenly the bd_mutex comes with a whole host of other dependencies,
which results in the splat when you mount a btrfs file system.
======================================================
WARNING: possible circular locking dependency detected
5.8.0-0.rc3.1.fc33.x86_64+debug #1 Not tainted
------------------------------------------------------
systemd-journal/509 is trying to acquire lock:
ffff970831f84db0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x44/0x70 [btrfs]
but task is already holding lock:
ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #6 (sb_pagefaults){.+.+}-{0:0}:
__sb_start_write+0x13e/0x220
btrfs_page_mkwrite+0x59/0x560 [btrfs]
do_page_mkwrite+0x4f/0x130
do_wp_page+0x3b0/0x4f0
handle_mm_fault+0xf47/0x1850
do_user_addr_fault+0x1fc/0x4b0
exc_page_fault+0x88/0x300
asm_exc_page_fault+0x1e/0x30
-> #5 (&mm->mmap_lock#2){++++}-{3:3}:
__might_fault+0x60/0x80
_copy_from_user+0x20/0xb0
get_sg_io_hdr+0x9a/0xb0
scsi_cmd_ioctl+0x1ea/0x2f0
cdrom_ioctl+0x3c/0x12b4
sr_block_ioctl+0xa4/0xd0
block_ioctl+0x3f/0x50
ksys_ioctl+0x82/0xc0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x52/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #4 (&cd->lock){+.+.}-{3:3}:
__mutex_lock+0x7b/0x820
sr_block_open+0xa2/0x180
__blkdev_get+0xdd/0x550
blkdev_get+0x38/0x150
do_dentry_open+0x16b/0x3e0
path_openat+0x3c9/0xa00
do_filp_open+0x75/0x100
do_sys_openat2+0x8a/0x140
__x64_sys_openat+0x46/0x70
do_syscall_64+0x52/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #3 (&bdev->bd_mutex){+.+.}-{3:3}:
__mutex_lock+0x7b/0x820
__blkdev_get+0x6a/0x550
blkdev_get+0x85/0x150
blkdev_get_by_path+0x2c/0x70
btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs]
open_fs_devices+0x88/0x240 [btrfs]
btrfs_open_devices+0x92/0xa0 [btrfs]
btrfs_mount_root+0x250/0x490 [btrfs]
legacy_get_tree+0x30/0x50
vfs_get_tree+0x28/0xc0
vfs_kern_mount.part.0+0x71/0xb0
btrfs_mount+0x119/0x380 [btrfs]
legacy_get_tree+0x30/0x50
vfs_get_tree+0x28/0xc0
do_mount+0x8c6/0xca0
__x64_sys_mount+0x8e/0xd0
do_syscall_64+0x52/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
__mutex_lock+0x7b/0x820
btrfs_run_dev_stats+0x36/0x420 [btrfs]
commit_cowonly_roots+0x91/0x2d0 [btrfs]
btrfs_commit_transaction+0x4e6/0x9f0 [btrfs]
btrfs_sync_file+0x38a/0x480 [btrfs]
__x64_sys_fdatasync+0x47/0x80
do_syscall_64+0x52/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
__mutex_lock+0x7b/0x820
btrfs_commit_transaction+0x48e/0x9f0 [btrfs]
btrfs_sync_file+0x38a/0x480 [btrfs]
__x64_sys_fdatasync+0x47/0x80
do_syscall_64+0x52/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}:
__lock_acquire+0x1241/0x20c0
lock_acquire+0xb0/0x400
__mutex_lock+0x7b/0x820
btrfs_record_root_in_trans+0x44/0x70 [btrfs]
start_transaction+0xd2/0x500 [btrfs]
btrfs_dirty_inode+0x44/0xd0 [btrfs]
file_update_time+0xc6/0x120
btrfs_page_mkwrite+0xda/0x560 [btrfs]
do_page_mkwrite+0x4f/0x130
do_wp_page+0x3b0/0x4f0
handle_mm_fault+0xf47/0x1850
do_user_addr_fault+0x1fc/0x4b0
exc_page_fault+0x88/0x300
asm_exc_page_fault+0x1e/0x30
other info that might help us debug this:
Chain exists of:
&fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sb_pagefaults);
lock(&mm->mmap_lock#2);
lock(sb_pagefaults);
lock(&fs_info->reloc_mutex);
*** DEADLOCK ***
3 locks held by systemd-journal/509:
#0: ffff97083bdec8b8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x12e/0x4b0
#1: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs]
#2: ffff97083144d6a8 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3f8/0x500 [btrfs]
stack backtrace:
CPU: 0 PID: 509 Comm: systemd-journal Not tainted 5.8.0-0.rc3.1.fc33.x86_64+debug #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
dump_stack+0x92/0xc8
check_noncircular+0x134/0x150
__lock_acquire+0x1241/0x20c0
lock_acquire+0xb0/0x400
? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
? lock_acquire+0xb0/0x400
? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
__mutex_lock+0x7b/0x820
? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
? kvm_sched_clock_read+0x14/0x30
? sched_clock+0x5/0x10
? sched_clock_cpu+0xc/0xb0
btrfs_record_root_in_trans+0x44/0x70 [btrfs]
start_transaction+0xd2/0x500 [btrfs]
btrfs_dirty_inode+0x44/0xd0 [btrfs]
file_update_time+0xc6/0x120
btrfs_page_mkwrite+0xda/0x560 [btrfs]
? sched_clock+0x5/0x10
do_page_mkwrite+0x4f/0x130
do_wp_page+0x3b0/0x4f0
handle_mm_fault+0xf47/0x1850
do_user_addr_fault+0x1fc/0x4b0
exc_page_fault+0x88/0x300
? asm_exc_page_fault+0x8/0x30
asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x7fa3972fdbfe
Code: Bad RIP value.
Fix this by not holding the ->device_list_mutex at this point. The
device_list_mutex exists to protect us from modifying the device list
while the file system is running.
However it can also be modified by doing a scan on a device. But this
action is specifically protected by the uuid_mutex, which we are holding
here. We cannot race with opening at this point because we have the
->s_mount lock held during the mount. Not having the
->device_list_mutex here is perfectly safe as we're not going to change
the devices at this point.
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add some comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
commit c92d30e upstream.
In commit f3b98e3 ("media: vsp1: Provide support for extended
command pools"), the vsp pointer used for referencing the VSP1 device
structure from a command pool during vsp1_dl_ext_cmd_pool_destroy() was
not populated.
Correctly assign the pointer to prevent the following
null-pointer-dereference when removing the device:
[*] h3ulcb-kf #>
echo fea28000.vsp > /sys/bus/platform/devices/fea28000.vsp/driver/unbind
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000028
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=00000007318be000
[0000000000000028] pgd=00000007333a1003, pud=00000007333a6003, pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 486 Comm: sh Not tainted 5.7.0-rc6-arm64-renesas-00118-ge644645abf47 #185
Hardware name: Renesas H3ULCB Kingfisher board based on r8a77951 (DT)
pstate: 40000005 (nZcv daif -PAN -UAO)
pc : vsp1_dlm_destroy+0xe4/0x11c
lr : vsp1_dlm_destroy+0xc8/0x11c
sp : ffff800012963b60
x29: ffff800012963b60 x28: ffff0006f83fc440
x27: 0000000000000000 x26: ffff0006f5e13e80
x25: ffff0006f5e13ed0 x24: ffff0006f5e13ed0
x23: ffff0006f5e13ed0 x22: dead000000000122
x21: ffff0006f5e3a080 x20: ffff0006f5df2938
x19: ffff0006f5df2980 x18: 0000000000000003
x17: 0000000000000000 x16: 0000000000000016
x15: 0000000000000003 x14: 00000000000393c0
x13: ffff800011a5ec18 x12: ffff800011d8d000
x11: ffff0006f83fcc68 x10: ffff800011a53d70
x9 : ffff8000111f3000 x8 : 0000000000000000
x7 : 0000000000210d00 x6 : 0000000000000000
x5 : ffff800010872e60 x4 : 0000000000000004
x3 : 0000000078068000 x2 : ffff800012781000
x1 : 0000000000002c00 x0 : 0000000000000000
Call trace:
vsp1_dlm_destroy+0xe4/0x11c
vsp1_wpf_destroy+0x10/0x20
vsp1_entity_destroy+0x24/0x4c
vsp1_destroy_entities+0x54/0x130
vsp1_remove+0x1c/0x40
platform_drv_remove+0x28/0x50
__device_release_driver+0x178/0x220
device_driver_detach+0x44/0xc0
unbind_store+0xe0/0x104
drv_attr_store+0x20/0x30
sysfs_kf_write+0x48/0x70
kernfs_fop_write+0x148/0x230
__vfs_write+0x18/0x40
vfs_write+0xdc/0x1c4
ksys_write+0x68/0xf0
__arm64_sys_write+0x18/0x20
el0_svc_common.constprop.0+0x70/0x170
do_el0_svc+0x20/0x80
el0_sync_handler+0x134/0x1b0
el0_sync+0x140/0x180
Code: b40000c2 f9403a60 d2800084 a9400663 (f9401400)
---[ end trace 3875369841fb288a ]---
Fixes: f3b98e3 ("media: vsp1: Provide support for extended command pools")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit cb36e29 ]
When watchdog device is being registered, it calls misc_register that
makes watchdog available for systemd to open. This is a data race
scenario, because when device is open it may still have device struct
not initialized - this in turn causes a crash. This patch moves
device initialization before misc_register call and it solves the
problem printed below.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1 at lib/kobject.c:612 kobject_get+0x50/0x54
kobject: '(null)' ((ptrval)): is not initialized, yet kobject_get() is being called.
Modules linked in: k2_reset_status(O) davinci_wdt(+) sfn_platform_hwbcn(O) fsmddg_sfn(O) clk_misc_mmap(O) clk_sw_bcn(O) fsp_reset(O) cma_mod(O) slave_sup_notif(O) fpga_master(O) latency(O+) evnotify(O) enable_arm_pmu(O) xge(O) rio_mport_cdev br_netfilter bridge stp llc nvrd_checksum(O) ipv6
CPU: 3 PID: 1 Comm: systemd Tainted: G O 4.19.113-g2579778-fsm4_k2 #1
Hardware name: Keystone
[<c02126c4>] (unwind_backtrace) from [<c020da94>] (show_stack+0x18/0x1c)
[<c020da94>] (show_stack) from [<c07f87d8>] (dump_stack+0xb4/0xe8)
[<c07f87d8>] (dump_stack) from [<c0221f70>] (__warn+0xfc/0x114)
[<c0221f70>] (__warn) from [<c0221fd8>] (warn_slowpath_fmt+0x50/0x74)
[<c0221fd8>] (warn_slowpath_fmt) from [<c07fd394>] (kobject_get+0x50/0x54)
[<c07fd394>] (kobject_get) from [<c0602ce8>] (get_device+0x1c/0x24)
[<c0602ce8>] (get_device) from [<c06961e0>] (watchdog_open+0x90/0xf0)
[<c06961e0>] (watchdog_open) from [<c06001dc>] (misc_open+0x130/0x17c)
[<c06001dc>] (misc_open) from [<c0388228>] (chrdev_open+0xec/0x1a8)
[<c0388228>] (chrdev_open) from [<c037fa98>] (do_dentry_open+0x204/0x3cc)
[<c037fa98>] (do_dentry_open) from [<c0391e2c>] (path_openat+0x330/0x1148)
[<c0391e2c>] (path_openat) from [<c0394518>] (do_filp_open+0x78/0xec)
[<c0394518>] (do_filp_open) from [<c0381100>] (do_sys_open+0x130/0x1f4)
[<c0381100>] (do_sys_open) from [<c0201000>] (ret_fast_syscall+0x0/0x28)
Exception stack(0xd2ceffa8 to 0xd2cefff0)
ffa0: b6f69968 00000000 ffffff9c b6ebd210 000a0001 00000000
ffc0: b6f69968 00000000 00000000 00000142 fffffff ffffffff 00b65530 bed7bb78
ffe0: 00000142 bed7ba70 b6cc2503 b6cc41d6
---[ end trace 7b16eb105513974f ]---
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1 at lib/refcount.c:153 kobject_get+0x24/0x54
refcount_t: increment on 0; use-after-free.
Modules linked in: k2_reset_status(O) davinci_wdt(+) sfn_platform_hwbcn(O) fsmddg_sfn(O) clk_misc_mmap(O) clk_sw_bcn(O) fsp_reset(O) cma_mod(O) slave_sup_notif(O) fpga_master(O) latency(O+) evnotify(O) enable_arm_pmu(O) xge(O) rio_mport_cdev br_netfilter bridge stp llc nvrd_checksum(O) ipv6
CPU: 3 PID: 1 Comm: systemd Tainted: G W O 4.19.113-g2579778-fsm4_k2 #1
Hardware name: Keystone
[<c02126c4>] (unwind_backtrace) from [<c020da94>] (show_stack+0x18/0x1c)
[<c020da94>] (show_stack) from [<c07f87d8>] (dump_stack+0xb4/0xe8)
[<c07f87d8>] (dump_stack) from [<c0221f70>] (__warn+0xfc/0x114)
[<c0221f70>] (__warn) from [<c0221fd8>] (warn_slowpath_fmt+0x50/0x74)
[<c0221fd8>] (warn_slowpath_fmt) from [<c07fd368>] (kobject_get+0x24/0x54)
[<c07fd368>] (kobject_get) from [<c0602ce8>] (get_device+0x1c/0x24)
[<c0602ce8>] (get_device) from [<c06961e0>] (watchdog_open+0x90/0xf0)
[<c06961e0>] (watchdog_open) from [<c06001dc>] (misc_open+0x130/0x17c)
[<c06001dc>] (misc_open) from [<c0388228>] (chrdev_open+0xec/0x1a8)
[<c0388228>] (chrdev_open) from [<c037fa98>] (do_dentry_open+0x204/0x3cc)
[<c037fa98>] (do_dentry_open) from [<c0391e2c>] (path_openat+0x330/0x1148)
[<c0391e2c>] (path_openat) from [<c0394518>] (do_filp_open+0x78/0xec)
[<c0394518>] (do_filp_open) from [<c0381100>] (do_sys_open+0x130/0x1f4)
[<c0381100>] (do_sys_open) from [<c0201000>] (ret_fast_syscall+0x0/0x28)
Exception stack(0xd2ceffa8 to 0xd2cefff0)
ffa0: b6f69968 00000000 ffffff9c b6ebd210 000a0001 00000000
ffc0: b6f69968 00000000 00000000 00000142 fffffff ffffffff 00b65530 bed7bb78
ffe0: 00000142 bed7ba70 b6cc2503 b6cc41d6
---[ end trace 7b16eb1055139750 ]---
Fixes: 72139df ("watchdog: Fix the race between the release of watchdog_core_data and cdev")
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Krzysztof Sobota <krzysztof.sobota@nokia.com>
Link: https://lore.kernel.org/r/20200717103109.14660-1-krzysztof.sobota@nokia.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
…ression
[ Upstream commit 1e6e238 ]
[BUG]
There is a bug report of NULL pointer dereference caused in
compress_file_extent():
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Workqueue: btrfs-delalloc btrfs_delalloc_helper [btrfs]
NIP [c008000006dd4d34] compress_file_range.constprop.41+0x75c/0x8a0 [btrfs]
LR [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs]
Call Trace:
[c000000c69093b00] [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs] (unreliable)
[c000000c69093bd0] [c008000006dd4ebc] async_cow_start+0x44/0xa0 [btrfs]
[c000000c69093c10] [c008000006e14824] normal_work_helper+0xdc/0x598 [btrfs]
[c000000c69093c80] [c0000000001608c0] process_one_work+0x2c0/0x5b0
[c000000c69093d10] [c000000000160c38] worker_thread+0x88/0x660
[c000000c69093db0] [c00000000016b55c] kthread+0x1ac/0x1c0
[c000000c69093e20] [c00000000000b660] ret_from_kernel_thread+0x5c/0x7c
---[ end trace f16954aa20d822f6 ]---
[CAUSE]
For the following execution route of compress_file_range(), it's
possible to hit NULL pointer dereference:
compress_file_extent()
|- pages = NULL;
|- start = async_chunk->start = 0;
|- end = async_chunk = 4095;
|- nr_pages = 1;
|- inode_need_compress() == false; <<< Possible, see later explanation
| Now, we have nr_pages = 1, pages = NULL
|- cont:
|- ret = cow_file_range_inline();
|- if (ret <= 0) {
|- for (i = 0; i < nr_pages; i++) {
|- WARN_ON(pages[i]->mapping);	<<< Crash
To enter above call execution branch, we need the following race:
Thread 1 (chattr) | Thread 2 (writeback)
--------------------------+------------------------------
| btrfs_run_delalloc_range
| |- inode_need_compress = true
| |- cow_file_range_async()
btrfs_ioctl_set_flag() |
|- binode_flags |= |
BTRFS_INODE_NOCOMPRESS |
| compress_file_range()
| |- inode_need_compress = false
| |- nr_page = 1 while pages = NULL
| | Then hit the crash
[FIX]
This patch will fix it by checking @pages before doing accessing it.
This patch is only designed as a hot fix and easy to backport.
More elegant fix may make btrfs only check inode_need_compress() once to
avoid such race, but that would be another story.
Reported-by: Luciano Chavez <chavez@us.ibm.com>
Fixes: 4d3a800 ("btrfs: merge nr_pages input and output parameter in compress_pages")
CC: stable@vger.kernel.org # 4.14.x: cecc8d9: btrfs: Move free_pages_out label in inline extent handling branch in compress_file_range
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit a47bd78 ]
Dave hit this splat during testing btrfs/078:
======================================================
WARNING: possible circular locking dependency detected
5.8.0-rc6-default+ #1191 Not tainted
------------------------------------------------------
kswapd0/75 is trying to acquire lock:
ffffa040e9d04ff8 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
but task is already holding lock:
ffffffff8b0c8040 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (fs_reclaim){+.+.}-{0:0}:
__lock_acquire+0x56f/0xaa0
lock_acquire+0xa3/0x440
fs_reclaim_acquire.part.0+0x25/0x30
__kmalloc_track_caller+0x49/0x330
kstrdup+0x2e/0x60
__kernfs_new_node.constprop.0+0x44/0x250
kernfs_new_node+0x25/0x50
kernfs_create_link+0x34/0xa0
sysfs_do_create_link_sd+0x5e/0xd0
btrfs_sysfs_add_devices_dir+0x65/0x100 [btrfs]
btrfs_init_new_device+0x44c/0x12b0 [btrfs]
btrfs_ioctl+0xc3c/0x25c0 [btrfs]
ksys_ioctl+0x68/0xa0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x50/0xe0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
__lock_acquire+0x56f/0xaa0
lock_acquire+0xa3/0x440
__mutex_lock+0xa0/0xaf0
btrfs_chunk_alloc+0x137/0x3e0 [btrfs]
find_free_extent+0xb44/0xfb0 [btrfs]
btrfs_reserve_extent+0x9b/0x180 [btrfs]
btrfs_alloc_tree_block+0xc1/0x350 [btrfs]
alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs]
__btrfs_cow_block+0x143/0x7a0 [btrfs]
btrfs_cow_block+0x15f/0x310 [btrfs]
push_leaf_right+0x150/0x240 [btrfs]
split_leaf+0x3cd/0x6d0 [btrfs]
btrfs_search_slot+0xd14/0xf70 [btrfs]
btrfs_insert_empty_items+0x64/0xc0 [btrfs]
__btrfs_commit_inode_delayed_items+0xb2/0x840 [btrfs]
btrfs_async_run_delayed_root+0x10e/0x1d0 [btrfs]
btrfs_work_helper+0x2f9/0x650 [btrfs]
process_one_work+0x22c/0x600
worker_thread+0x50/0x3b0
kthread+0x137/0x150
ret_from_fork+0x1f/0x30
-> #0 (&delayed_node->mutex){+.+.}-{3:3}:
check_prev_add+0x98/0xa20
validate_chain+0xa8c/0x2a00
__lock_acquire+0x56f/0xaa0
lock_acquire+0xa3/0x440
__mutex_lock+0xa0/0xaf0
__btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
btrfs_evict_inode+0x3bf/0x560 [btrfs]
evict+0xd6/0x1c0
dispose_list+0x48/0x70
prune_icache_sb+0x54/0x80
super_cache_scan+0x121/0x1a0
do_shrink_slab+0x175/0x420
shrink_slab+0xb1/0x2e0
shrink_node+0x192/0x600
balance_pgdat+0x31f/0x750
kswapd+0x206/0x510
kthread+0x137/0x150
ret_from_fork+0x1f/0x30
other info that might help us debug this:
Chain exists of:
&delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&fs_info->chunk_mutex);
lock(fs_reclaim);
lock(&delayed_node->mutex);
*** DEADLOCK ***
3 locks held by kswapd0/75:
#0: ffffffff8b0c8040 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
#1: ffffffff8b0b50b8 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x54/0x2e0
#2: ffffa040e057c0e8 (&type->s_umount_key#26){++++}-{3:3}, at: trylock_super+0x16/0x50
stack backtrace:
CPU: 2 PID: 75 Comm: kswapd0 Not tainted 5.8.0-rc6-default+ #1191
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
Call Trace:
dump_stack+0x78/0xa0
check_noncircular+0x16f/0x190
check_prev_add+0x98/0xa20
validate_chain+0xa8c/0x2a00
__lock_acquire+0x56f/0xaa0
lock_acquire+0xa3/0x440
? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
__mutex_lock+0xa0/0xaf0
? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
? __lock_acquire+0x56f/0xaa0
? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
? lock_acquire+0xa3/0x440
? btrfs_evict_inode+0x138/0x560 [btrfs]
? btrfs_evict_inode+0x2fe/0x560 [btrfs]
? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
__btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
btrfs_evict_inode+0x3bf/0x560 [btrfs]
evict+0xd6/0x1c0
dispose_list+0x48/0x70
prune_icache_sb+0x54/0x80
super_cache_scan+0x121/0x1a0
do_shrink_slab+0x175/0x420
shrink_slab+0xb1/0x2e0
shrink_node+0x192/0x600
balance_pgdat+0x31f/0x750
kswapd+0x206/0x510
? _raw_spin_unlock_irqrestore+0x3e/0x50
? finish_wait+0x90/0x90
? balance_pgdat+0x750/0x750
kthread+0x137/0x150
? kthread_stop+0x2a0/0x2a0
ret_from_fork+0x1f/0x30
This is because we're holding the chunk_mutex while adding this device
and adding its sysfs entries. We actually hold different locks in
different places when calling this function, the dev_replace semaphore
for instance in dev replace, so instead of moving this call around
simply wrap it's operations in NOFS.
CC: stable@vger.kernel.org # 4.14+
Reported-by: David Sterba <dsterba@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
[ Upstream commit 5b6d4a7 ]
Fix the reason of crashing system by add waiting time to finish reset
recovery process before starting remove driver procedure.
Now VSI is releasing if VSI is not in reset recovery mode.
Without this fix it was possible to start remove driver if other
processing command need reset recovery procedure which resulted in
null pointer dereference. VSI used by the ethtool process has been
cleared by remove driver process.
[ 6731.508665] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 6731.508668] #PF: supervisor read access in kernel mode
[ 6731.508670] #PF: error_code(0x0000) - not-present page
[ 6731.508671] PGD 0 P4D 0
[ 6731.508674] Oops: 0000 [#1] SMP PTI
[ 6731.508679] Hardware name: Intel Corporation S2600WT2R/S2600WT2R, BIOS SE5C610.86B.01.01.0021.032120170601 03/21/2017
[ 6731.508694] RIP: 0010:i40e_down+0x252/0x310 [i40e]
[ 6731.508696] Code: c7 78 de fa c0 e8 61 02 3a c1 66 83 bb f6 0c 00 00 00 0f 84 bf 00 00 00 45 31 e4 45 31 ff eb 03 41 89 c7 48 8b 83 98 0c 00 00 <4a> 8b 3c 20 e8 a5 79 02 00 48 83 bb d0 0c 00 00 00 74 10 48 8b 83
[ 6731.508698] RSP: 0018:ffffb75ac7b3faf0 EFLAGS: 00010246
[ 6731.508700] RAX: 0000000000000000 RBX: ffff9c9874bd5000 RCX: 0000000000000007
[ 6731.508701] RDX: 0000000000000000 RSI: 0000000000000096 RDI: ffff9c987f4d9780
[ 6731.508703] RBP: ffffb75ac7b3fb30 R08: 0000000000005b60 R09: 0000000000000004
[ 6731.508704] R10: ffffb75ac64fbd90 R11: 0000000000000001 R12: 0000000000000000
[ 6731.508706] R13: ffff9c97a08e0000 R14: ffff9c97a08e0a68 R15: 0000000000000000
[ 6731.508708] FS: 00007f2617cd2740(0000) GS:ffff9c987f4c0000(0000) knlGS:0000000000000000
[ 6731.508710] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 6731.508711] CR2: 0000000000000000 CR3: 0000001e765c4006 CR4: 00000000003606e0
[ 6731.508713] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 6731.508714] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 6731.508715] Call Trace:
[ 6731.508734] i40e_vsi_close+0x84/0x90 [i40e]
[ 6731.508742] i40e_quiesce_vsi.part.98+0x3c/0x40 [i40e]
[ 6731.508749] i40e_pf_quiesce_all_vsi+0x55/0x60 [i40e]
[ 6731.508757] i40e_prep_for_reset+0x59/0x130 [i40e]
[ 6731.508765] i40e_reconfig_rss_queues+0x5a/0x120 [i40e]
[ 6731.508774] i40e_set_channels+0xda/0x170 [i40e]
[ 6731.508778] ethtool_set_channels+0xe9/0x150
[ 6731.508781] dev_ethtool+0x1b94/0x2920
[ 6731.508805] dev_ioctl+0xc2/0x590
[ 6731.508811] sock_do_ioctl+0xae/0x150
[ 6731.508813] sock_ioctl+0x34f/0x3c0
[ 6731.508821] ksys_ioctl+0x98/0xb0
[ 6731.508828] __x64_sys_ioctl+0x1a/0x20
[ 6731.508831] do_syscall_64+0x57/0x1c0
[ 6731.508835] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: 4b81644 ("i40e: Add common function for finding VSI by type")
Signed-off-by: Grzegorz Szczurek <grzegorzx.szczurek@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
For support of long running hypercalls xen_maybe_preempt_hcall() is
calling cond_resched() in case a hypercall marked as preemptible has
been interrupted.
Normally this is no problem, as only hypercalls done via some ioctl()s
are marked to be preemptible. In rare cases when during such a
preemptible hypercall an interrupt occurs and any softirq action is
started from irq_exit(), a further hypercall issued by the softirq
handler will be regarded to be preemptible, too. This might lead to
rescheduling in spite of the softirq handler potentially having set
preempt_disable(), leading to splats like:
BUG: sleeping function called from invalid context at drivers/xen/preempt.c:37
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 20775, name: xl
INFO: lockdep is turned off.
CPU: 1 PID: 20775 Comm: xl Tainted: G D W 5.4.46-1_prgmr_debug.el7.x86_64 #1
Call Trace:
<IRQ>
dump_stack+0x8f/0xd0
___might_sleep.cold.76+0xb2/0x103
xen_maybe_preempt_hcall+0x48/0x70
xen_do_hypervisor_callback+0x37/0x40
RIP: e030:xen_hypercall_xen_version+0xa/0x20
Code: ...
RSP: e02b:ffffc900400dcc30 EFLAGS: 00000246
RAX: 000000000004000d RBX: 0000000000000200 RCX: ffffffff8100122a
RDX: ffff88812e788000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff83ee3ad0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: ffff8881824aa0b0
R13: 0000000865496000 R14: 0000000865496000 R15: ffff88815d040000
? xen_hypercall_xen_version+0xa/0x20
? xen_force_evtchn_callback+0x9/0x10
? check_events+0x12/0x20
? xen_restore_fl_direct+0x1f/0x20
? _raw_spin_unlock_irqrestore+0x53/0x60
? debug_dma_sync_single_for_cpu+0x91/0xc0
? _raw_spin_unlock_irqrestore+0x53/0x60
? xen_swiotlb_sync_single_for_cpu+0x3d/0x140
? mlx4_en_process_rx_cq+0x6b6/0x1110 [mlx4_en]
? mlx4_en_poll_rx_cq+0x64/0x100 [mlx4_en]
? net_rx_action+0x151/0x4a0
? __do_softirq+0xed/0x55b
? irq_exit+0xea/0x100
? xen_evtchn_do_upcall+0x2c/0x40
? xen_do_hypervisor_callback+0x29/0x40
</IRQ>
? xen_hypercall_domctl+0xa/0x20
? xen_hypercall_domctl+0x8/0x20
? privcmd_ioctl+0x221/0x990 [xen_privcmd]
? do_vfs_ioctl+0xa5/0x6f0
? ksys_ioctl+0x60/0x90
? trace_hardirqs_off_thunk+0x1a/0x20
? __x64_sys_ioctl+0x16/0x20
? do_syscall_64+0x62/0x250
? entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fix that by testing preempt_count() before calling cond_resched().
In kernel 5.8 this can't happen any more due to the entry code rework
(more than 100 patches, so not a candidate for backporting).
The issue was introduced in kernel 4.3, so this patch should go into
all stable kernels in [4.3 ... 5.7].
Reported-by: Sarah Newman <srn@prgmr.com>
Fixes: 0fa2f5c ("sched/preempt, xen: Use need_resched() instead of should_resched()")
Cc: Sarah Newman <srn@prgmr.com>
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Chris Brannon <cmb@prgmr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
VictorNogueiraRio pushed a commit that referenced this pull request Nov 17, 2020
commit b533137 upstream.
When an MMU notifier call results in unmapping a range that spans multiple
PGDs, we end up calling into cond_resched_lock() when crossing a PGD boundary,
since this avoids running into RCU stalls during VM teardown. Unfortunately,
if the VM is destroyed as a result of OOM, then blocking is not permitted
and the call to the scheduler triggers the following BUG():
| BUG: sleeping function called from invalid context at arch/arm64/kvm/mmu.c:394
| in_atomic(): 1, irqs_disabled(): 0, non_block: 1, pid: 36, name: oom_reaper
| INFO: lockdep is turned off.
| CPU: 3 PID: 36 Comm: oom_reaper Not tainted 5.8.0 #1
| Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
| Call trace:
| dump_backtrace+0x0/0x284
| show_stack+0x1c/0x28
| dump_stack+0xf0/0x1a4
| ___might_sleep+0x2bc/0x2cc
| unmap_stage2_range+0x160/0x1ac
| kvm_unmap_hva_range+0x1a0/0x1c8
| kvm_mmu_notifier_invalidate_range_start+0x8c/0xf8
| __mmu_notifier_invalidate_range_start+0x218/0x31c
| mmu_notifier_invalidate_range_start_nonblock+0x78/0xb0
| __oom_reap_task_mm+0x128/0x268
| oom_reap_task+0xac/0x298
| oom_reaper+0x178/0x17c
| kthread+0x1e4/0x1fc
| ret_from_fork+0x10/0x30
Use the new 'flags' argument to kvm_unmap_hva_range() to ensure that we
only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is set in the notifier
flags.
Cc: <stable@vger.kernel.org>
Fixes: 8b3405e ("kvm: arm/arm64: Fix locking for kvm_free_stage2_pgd")
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-3-will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[will: Backport to 4.19; use 'blockable' instead of non-existent MMU_NOTIFIER_RANGE_BLOCKABLE flag]
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@VictorNogueiraRio@mizvekov