[PATCH v2] kasan: remove kasan_find_vm_area() to prevent possible deadlock

From: Yeoreum Yun
Date: Thu Jul 03 2025 - 14:10:36 EST

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find_vm_area() couldn't be called in atomic_context.
If find_vm_area() is called to reports vm area information,
kasan can trigger deadlock like:

CPU0 CPU1
vmalloc();
alloc_vmap_area();
spin_lock(&vn->busy.lock)
spin_lock_bh(&some_lock);
<interrupt occurs>
<in softirq>
spin_lock(&some_lock);
<access invalid address>
kasan_report();
print_report();
print_address_description();
kasan_find_vm_area();
find_vm_area();
spin_lock(&vn->busy.lock) // deadlock!

To prevent possible deadlock while kasan reports, remove kasan_find_vm_area().

Fixes: c056a364e954 ("kasan: print virtual mapping info in reports")
Reported-by: Yunseong Kim <ysk@xxxxxxxxxxx>
Signed-off-by: Yeoreum Yun <yeoreum.yun@xxxxxxx>
---

Patch History
===============
>From v1 to v2:
- remove kasan_find_vm_area()
- v1: https://lore.kernel.org/all/20250701203545.216719-1-yeoreum.yun@xxxxxxx/

NOTE
===============
Below report is from Yunseong Kim using DEPT:

===================================================
DEPT: Circular dependency has been detected.
6.15.0-rc6-00043-ga83a69ec7f9f #5 Not tainted
---------------------------------------------------
summary
---------------------------------------------------
*** DEADLOCK ***

context A
[S] lock(report_lock:0)
[W] lock(&vn->busy.lock:0)
[E] unlock(report_lock:0)

context B
[S] lock(&tb->tb6_lock:0)
[W] lock(report_lock:0)
[E] unlock(&tb->tb6_lock:0)

context C
[S] write_lock(&ndev->lock:0)
[W] lock(&tb->tb6_lock:0)
[E] write_unlock(&ndev->lock:0)

context D
[S] lock(&vn->busy.lock:0)
[W] write_lock(&ndev->lock:0)
[E] unlock(&vn->busy.lock:0)

[S]: start of the event context
[W]: the wait blocked
[E]: the event not reachable
---------------------------------------------------
context A's detail
---------------------------------------------------
context A
[S] lock(report_lock:0)
[W] lock(&vn->busy.lock:0)
[E] unlock(report_lock:0)

[S] lock(report_lock:0):
[<ffff800080bd2600>] start_report mm/kasan/report.c:215 [inline]
[<ffff800080bd2600>] kasan_report+0x74/0x1d4 mm/kasan/report.c:623
stacktrace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x88/0xd8 kernel/locking/spinlock.c:162
start_report mm/kasan/report.c:215 [inline]
kasan_report+0x74/0x1d4 mm/kasan/report.c:623
__asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
fib6_ifdown+0x67c/0x6bc net/ipv6/route.c:4910
fib6_clean_node+0x23c/0x4e0 net/ipv6/ip6_fib.c:2199
fib6_walk_continue+0x38c/0x774 net/ipv6/ip6_fib.c:2124
fib6_walk+0x158/0x31c net/ipv6/ip6_fib.c:2172
fib6_clean_tree+0xe0/0x128 net/ipv6/ip6_fib.c:2252
__fib6_clean_all+0x104/0x2b8 net/ipv6/ip6_fib.c:2268
fib6_clean_all+0x3c/0x50 net/ipv6/ip6_fib.c:2279
rt6_sync_down_dev net/ipv6/route.c:4951 [inline]
rt6_disable_ip+0x270/0x840 net/ipv6/route.c:4956
addrconf_ifdown.isra.0+0x104/0x175c net/ipv6/addrconf.c:3857
addrconf_notify+0x3a0/0x1688 net/ipv6/addrconf.c:3780
notifier_call_chain+0x94/0x50c kernel/notifier.c:85
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
call_netdevice_notifiers_info+0xb8/0x150 net/core/dev.c:2176

[W] lock(&vn->busy.lock:0):
[<ffff800080ae57a0>] spin_lock include/linux/spinlock.h:351 [inline]
[<ffff800080ae57a0>] find_vmap_area+0xa0/0x228 mm/vmalloc.c:2418
stacktrace:
spin_lock include/linux/spinlock.h:351 [inline]
find_vmap_area+0xa0/0x228 mm/vmalloc.c:2418
find_vm_area+0x20/0x68 mm/vmalloc.c:3208
kasan_find_vm_area mm/kasan/report.c:398 [inline]
print_address_description mm/kasan/report.c:432 [inline]
print_report+0x3d8/0x54c mm/kasan/report.c:521
kasan_report+0xb8/0x1d4 mm/kasan/report.c:634
__asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
fib6_ifdown+0x67c/0x6bc net/ipv6/route.c:4910
fib6_clean_node+0x23c/0x4e0 net/ipv6/ip6_fib.c:2199
fib6_walk_continue+0x38c/0x774 net/ipv6/ip6_fib.c:2124
fib6_walk+0x158/0x31c net/ipv6/ip6_fib.c:2172
fib6_clean_tree+0xe0/0x128 net/ipv6/ip6_fib.c:2252
__fib6_clean_all+0x104/0x2b8 net/ipv6/ip6_fib.c:2268
fib6_clean_all+0x3c/0x50 net/ipv6/ip6_fib.c:2279
rt6_sync_down_dev net/ipv6/route.c:4951 [inline]
rt6_disable_ip+0x270/0x840 net/ipv6/route.c:4956
addrconf_ifdown.isra.0+0x104/0x175c net/ipv6/addrconf.c:3857
addrconf_notify+0x3a0/0x1688 net/ipv6/addrconf.c:3780
notifier_call_chain+0x94/0x50c kernel/notifier.c:85

[E] unlock(report_lock:0):
(N/A)
---------------------------------------------------
context B's detail
---------------------------------------------------
context B
[S] lock(&tb->tb6_lock:0)
[W] lock(report_lock:0)
[E] unlock(&tb->tb6_lock:0)

[S] lock(&tb->tb6_lock:0):
[<ffff80008a172d10>] spin_lock_bh include/linux/spinlock.h:356 [inline]
[<ffff80008a172d10>] __fib6_clean_all+0xe8/0x2b8 net/ipv6/ip6_fib.c:2267
stacktrace:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x80/0xd0 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
__fib6_clean_all+0xe8/0x2b8 net/ipv6/ip6_fib.c:2267
fib6_clean_all+0x3c/0x50 net/ipv6/ip6_fib.c:2279
rt6_sync_down_dev net/ipv6/route.c:4951 [inline]
rt6_disable_ip+0x270/0x840 net/ipv6/route.c:4956
addrconf_ifdown.isra.0+0x104/0x175c net/ipv6/addrconf.c:3857
addrconf_notify+0x3a0/0x1688 net/ipv6/addrconf.c:3780
notifier_call_chain+0x94/0x50c kernel/notifier.c:85
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
call_netdevice_notifiers_info+0xb8/0x150 net/core/dev.c:2176
call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
call_netdevice_notifiers net/core/dev.c:2228 [inline]
dev_close_many+0x290/0x4b8 net/core/dev.c:1731
unregister_netdevice_many_notify+0x574/0x1fa0 net/core/dev.c:11940
unregister_netdevice_many net/core/dev.c:12034 [inline]
unregister_netdevice_queue+0x2b8/0x390 net/core/dev.c:11877
unregister_netdevice include/linux/netdevice.h:3374 [inline]
__tun_detach+0xec4/0x1180 drivers/net/tun.c:620
tun_detach drivers/net/tun.c:636 [inline]
tun_chr_close+0xa4/0x248 drivers/net/tun.c:3390
__fput+0x374/0xa30 fs/file_table.c:465
____fput+0x20/0x3c fs/file_table.c:493

[W] lock(report_lock:0):
[<ffff800080bd2600>] start_report mm/kasan/report.c:215 [inline]
[<ffff800080bd2600>] kasan_report+0x74/0x1d4 mm/kasan/report.c:623
stacktrace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x6c/0xd8 kernel/locking/spinlock.c:162
start_report mm/kasan/report.c:215 [inline]
kasan_report+0x74/0x1d4 mm/kasan/report.c:623
__asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
fib6_ifdown+0x67c/0x6bc net/ipv6/route.c:4910
fib6_clean_node+0x23c/0x4e0 net/ipv6/ip6_fib.c:2199
fib6_walk_continue+0x38c/0x774 net/ipv6/ip6_fib.c:2124
fib6_walk+0x158/0x31c net/ipv6/ip6_fib.c:2172
fib6_clean_tree+0xe0/0x128 net/ipv6/ip6_fib.c:2252
__fib6_clean_all+0x104/0x2b8 net/ipv6/ip6_fib.c:2268
fib6_clean_all+0x3c/0x50 net/ipv6/ip6_fib.c:2279
rt6_sync_down_dev net/ipv6/route.c:4951 [inline]
rt6_disable_ip+0x270/0x840 net/ipv6/route.c:4956
addrconf_ifdown.isra.0+0x104/0x175c net/ipv6/addrconf.c:3857
addrconf_notify+0x3a0/0x1688 net/ipv6/addrconf.c:3780
notifier_call_chain+0x94/0x50c kernel/notifier.c:85
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
call_netdevice_notifiers_info+0xb8/0x150 net/core/dev.c:2176

[E] unlock(&tb->tb6_lock:0):
(N/A)
---------------------------------------------------
context C's detail
---------------------------------------------------
context C
[S] write_lock(&ndev->lock:0)
[W] lock(&tb->tb6_lock:0)
[E] write_unlock(&ndev->lock:0)

[S] write_lock(&ndev->lock:0):
[<ffff80008a133bd8>] addrconf_permanent_addr net/ipv6/addrconf.c:3622 [inline]
[<ffff80008a133bd8>] addrconf_notify+0xab4/0x1688 net/ipv6/addrconf.c:3698
stacktrace:
__raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline]
_raw_write_lock_bh+0x88/0xd4 kernel/locking/spinlock.c:334
addrconf_permanent_addr net/ipv6/addrconf.c:3622 [inline]
addrconf_notify+0xab4/0x1688 net/ipv6/addrconf.c:3698
notifier_call_chain+0x94/0x50c kernel/notifier.c:85
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
call_netdevice_notifiers_info+0xb8/0x150 net/core/dev.c:2176
call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
call_netdevice_notifiers net/core/dev.c:2228 [inline]
__dev_notify_flags+0x114/0x294 net/core/dev.c:9393
netif_change_flags+0x108/0x160 net/core/dev.c:9422
do_setlink.isra.0+0x960/0x3464 net/core/rtnetlink.c:3152
rtnl_changelink net/core/rtnetlink.c:3769 [inline]
__rtnl_newlink net/core/rtnetlink.c:3928 [inline]
rtnl_newlink+0x1080/0x1a1c net/core/rtnetlink.c:4065
rtnetlink_rcv_msg+0x82c/0xc30 net/core/rtnetlink.c:6955
netlink_rcv_skb+0x218/0x400 net/netlink/af_netlink.c:2534
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6982
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x50c/0x778 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x794/0xc28 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0xe0/0x1a0 net/socket.c:727
__sys_sendto+0x238/0x2fc net/socket.c:2180

[W] lock(&tb->tb6_lock:0):
[<ffff80008a1643fc>] spin_lock_bh include/linux/spinlock.h:356 [inline]
[<ffff80008a1643fc>] __ip6_ins_rt net/ipv6/route.c:1350 [inline]
[<ffff80008a1643fc>] ip6_route_add+0x7c/0x220 net/ipv6/route.c:3900
stacktrace:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x5c/0xd0 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
__ip6_ins_rt net/ipv6/route.c:1350 [inline]
ip6_route_add+0x7c/0x220 net/ipv6/route.c:3900
addrconf_prefix_route+0x28c/0x494 net/ipv6/addrconf.c:2487
fixup_permanent_addr net/ipv6/addrconf.c:3602 [inline]
addrconf_permanent_addr net/ipv6/addrconf.c:3626 [inline]
addrconf_notify+0xfd0/0x1688 net/ipv6/addrconf.c:3698
notifier_call_chain+0x94/0x50c kernel/notifier.c:85
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
call_netdevice_notifiers_info+0xb8/0x150 net/core/dev.c:2176
call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
call_netdevice_notifiers net/core/dev.c:2228 [inline]
__dev_notify_flags+0x114/0x294 net/core/dev.c:9393
netif_change_flags+0x108/0x160 net/core/dev.c:9422
do_setlink.isra.0+0x960/0x3464 net/core/rtnetlink.c:3152
rtnl_changelink net/core/rtnetlink.c:3769 [inline]
__rtnl_newlink net/core/rtnetlink.c:3928 [inline]
rtnl_newlink+0x1080/0x1a1c net/core/rtnetlink.c:4065
rtnetlink_rcv_msg+0x82c/0xc30 net/core/rtnetlink.c:6955
netlink_rcv_skb+0x218/0x400 net/netlink/af_netlink.c:2534
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6982
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x50c/0x778 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x794/0xc28 net/netlink/af_netlink.c:1883

[E] write_unlock(&ndev->lock:0):
(N/A)
---------------------------------------------------
context D's detail
---------------------------------------------------
context D
[S] lock(&vn->busy.lock:0)
[W] write_lock(&ndev->lock:0)
[E] unlock(&vn->busy.lock:0)

[S] lock(&vn->busy.lock:0):
[<ffff800080adcf80>] spin_lock include/linux/spinlock.h:351 [inline]
[<ffff800080adcf80>] alloc_vmap_area+0x800/0x26d0 mm/vmalloc.c:2027
stacktrace:
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x78/0xc0 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
alloc_vmap_area+0x800/0x26d0 mm/vmalloc.c:2027
__get_vm_area_node+0x1c8/0x360 mm/vmalloc.c:3138
__vmalloc_node_range_noprof+0x168/0x10d4 mm/vmalloc.c:3805
__vmalloc_node_noprof+0x130/0x178 mm/vmalloc.c:3908
vzalloc_noprof+0x3c/0x54 mm/vmalloc.c:3981
alloc_counters net/ipv6/netfilter/ip6_tables.c:815 [inline]
copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
do_ip6t_get_ctl+0x520/0xad0 net/ipv6/netfilter/ip6_tables.c:1677
nf_getsockopt+0x8c/0x10c net/netfilter/nf_sockopt.c:116
ipv6_getsockopt+0x24c/0x460 net/ipv6/ipv6_sockglue.c:1493
tcp_getsockopt+0x98/0x120 net/ipv4/tcp.c:4727
sock_common_getsockopt+0x9c/0xcc net/core/sock.c:3867
do_sock_getsockopt+0x308/0x57c net/socket.c:2357
__sys_getsockopt+0xec/0x188 net/socket.c:2386
__do_sys_getsockopt net/socket.c:2393 [inline]
__se_sys_getsockopt net/socket.c:2390 [inline]
__arm64_sys_getsockopt+0xa8/0x110 net/socket.c:2390
__invoke_syscall arch/arm64/kernel/syscall.c:36 [inline]
invoke_syscall+0x88/0x2e0 arch/arm64/kernel/syscall.c:50
el0_svc_common.constprop.0+0xe8/0x2e0 arch/arm64/kernel/syscall.c:139

[W] write_lock(&ndev->lock:0):
[<ffff80008a127f20>] addrconf_rs_timer+0xa0/0x730 net/ipv6/addrconf.c:4025
stacktrace:
__raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
_raw_write_lock+0x5c/0xd0 kernel/locking/spinlock.c:300
addrconf_rs_timer+0xa0/0x730 net/ipv6/addrconf.c:4025
call_timer_fn+0x204/0x964 kernel/time/timer.c:1789
expire_timers kernel/time/timer.c:1840 [inline]
__run_timers+0x830/0xb00 kernel/time/timer.c:2414
__run_timer_base kernel/time/timer.c:2426 [inline]
__run_timer_base kernel/time/timer.c:2418 [inline]
run_timer_base+0x124/0x198 kernel/time/timer.c:2435
run_timer_softirq+0x20/0x58 kernel/time/timer.c:2445
handle_softirqs+0x30c/0xdc0 kernel/softirq.c:579
__do_softirq+0x14/0x20 kernel/softirq.c:613
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:81
call_on_irq_stack+0x24/0x30 arch/arm64/kernel/entry.S:891
do_softirq_own_stack+0x20/0x40 arch/arm64/kernel/irq.c:86
invoke_softirq kernel/softirq.c:460 [inline]
__irq_exit_rcu+0x400/0x560 kernel/softirq.c:680
irq_exit_rcu+0x14/0x80 kernel/softirq.c:696
__el1_irq arch/arm64/kernel/entry-common.c:561 [inline]
el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:575
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:580
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:596

[E] unlock(&vn->busy.lock:0):
(N/A)
---------------------------------------------------
information that might be helpful
---------------------------------------------------
CPU: 1 UID: 0 PID: 19536 Comm: syz.4.2592 Not tainted 6.15.0-rc6-00043-ga83a69ec7f9f #5 PREEMPT
Hardware name: QEMU KVM Virtual Machine, BIOS 2025.02-8 05/13/2025
Call trace:
dump_backtrace arch/arm64/kernel/stacktrace.c:449 [inline] (C)
show_stack+0x34/0x80 arch/arm64/kernel/stacktrace.c:466 (C)
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x104/0x180 lib/dump_stack.c:120
dump_stack+0x20/0x2c lib/dump_stack.c:129
print_circle kernel/dependency/dept.c:928 [inline]
cb_check_dl kernel/dependency/dept.c:1362 [inline]
cb_check_dl+0x1080/0x10ec kernel/dependency/dept.c:1356
bfs+0x4d8/0x630 kernel/dependency/dept.c:980
check_dl_bfs kernel/dependency/dept.c:1381 [inline]
add_dep+0x1cc/0x364 kernel/dependency/dept.c:1710
add_wait kernel/dependency/dept.c:1829 [inline]
__dept_wait+0x60c/0x16e0 kernel/dependency/dept.c:2585
dept_wait kernel/dependency/dept.c:2666 [inline]
dept_wait+0x168/0x1a8 kernel/dependency/dept.c:2640
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x54/0xc0 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
find_vmap_area+0xa0/0x228 mm/vmalloc.c:2418
find_vm_area+0x20/0x68 mm/vmalloc.c:3208
kasan_find_vm_area mm/kasan/report.c:398 [inline]
print_address_description mm/kasan/report.c:432 [inline]
print_report+0x3d8/0x54c mm/kasan/report.c:521
kasan_report+0xb8/0x1d4 mm/kasan/report.c:634
__asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
fib6_ifdown+0x67c/0x6bc net/ipv6/route.c:4910
fib6_clean_node+0x23c/0x4e0 net/ipv6/ip6_fib.c:2199
fib6_walk_continue+0x38c/0x774 net/ipv6/ip6_fib.c:2124
fib6_walk+0x158/0x31c net/ipv6/ip6_fib.c:2172
fib6_clean_tree+0xe0/0x128 net/ipv6/ip6_fib.c:2252
__fib6_clean_all+0x104/0x2b8 net/ipv6/ip6_fib.c:2268
fib6_clean_all+0x3c/0x50 net/ipv6/ip6_fib.c:2279
rt6_sync_down_dev net/ipv6/route.c:4951 [inline]
rt6_disable_ip+0x270/0x840 net/ipv6/route.c:4956
addrconf_ifdown.isra.0+0x104/0x175c net/ipv6/addrconf.c:3857
addrconf_notify+0x3a0/0x1688 net/ipv6/addrconf.c:3780
notifier_call_chain+0x94/0x50c kernel/notifier.c:85
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:453
call_netdevice_notifiers_info+0xb8/0x150 net/core/dev.c:2176
call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
call_netdevice_notifiers net/core/dev.c:2228 [inline]
dev_close_many+0x290/0x4b8 net/core/dev.c:1731
unregister_netdevice_many_notify+0x574/0x1fa0 net/core/dev.c:11940
unregister_netdevice_many net/core/dev.c:12034 [inline]
unregister_netdevice_queue+0x2b8/0x390 net/core/dev.c:11877
unregister_netdevice include/linux/netdevice.h:3374 [inline]
__tun_detach+0xec4/0x1180 drivers/net/tun.c:620
tun_detach drivers/net/tun.c:636 [inline]
tun_chr_close+0xa4/0x248 drivers/net/tun.c:3390
__fput+0x374/0xa30 fs/file_table.c:465
____fput+0x20/0x3c fs/file_table.c:493
task_work_run+0x154/0x278 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x950/0x23a8 kernel/exit.c:953
do_group_exit+0xc0/0x248 kernel/exit.c:1103
get_signal+0x1f98/0x20cc kernel/signal.c:3034
do_signal+0x200/0x880 arch/arm64/kernel/signal.c:1658
do_notify_resume+0x1a0/0x26c arch/arm64/kernel/entry-common.c:148
exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
el0_svc+0xf8/0x188 arch/arm64/kernel/entry-common.c:745
el0t_64_sync_handler+0x10c/0x140 arch/arm64/kernel/entry-common.c:762
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

---
mm/kasan/report.c | 45 ++-------------------------------------------
1 file changed, 2 insertions(+), 43 deletions(-)

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8357e1a33699..b0877035491f 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -370,36 +370,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}

-/*
- * This function is invoked with report_lock (a raw_spinlock) held. A
- * PREEMPT_RT kernel cannot call find_vm_area() as it will acquire a sleeping
- * rt_spinlock.
- *
- * For !RT kernel, the PROVE_RAW_LOCK_NESTING config option will print a
- * lockdep warning for this raw_spinlock -> spinlock dependency. This config
- * option is enabled by default to ensure better test coverage to expose this
- * kind of RT kernel problem. This lockdep splat, however, can be suppressed
- * by using DEFINE_WAIT_OVERRIDE_MAP() if it serves a useful purpose and the
- * invalid PREEMPT_RT case has been taken care of.
- */
-static inline struct vm_struct *kasan_find_vm_area(void *addr)
-{
- static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP);
- struct vm_struct *va;
-
- if (IS_ENABLED(CONFIG_PREEMPT_RT))
- return NULL;
-
- /*
- * Suppress lockdep warning and fetch vmalloc area of the
- * offending address.
- */
- lock_map_acquire_try(&vmalloc_map);
- va = find_vm_area(addr);
- lock_map_release(&vmalloc_map);
- return va;
-}
-
static void print_address_description(void *addr, u8 tag,
struct kasan_report_info *info)
{
@@ -429,19 +399,8 @@ static void print_address_description(void *addr, u8 tag,
}

if (is_vmalloc_addr(addr)) {
- struct vm_struct *va = kasan_find_vm_area(addr);
-
- if (va) {
- pr_err("The buggy address belongs to the virtual mapping at\n"
- " [%px, %px) created by:\n"
- " %pS\n",
- va->addr, va->addr + va->size, va->caller);
- pr_err("\n");
-
- page = vmalloc_to_page(addr);
- } else {
- pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
- }
+ pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
+ page = vmalloc_to_page(addr);
}

if (page) {
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}

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