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Date:   Mon, 15 Feb 2021 16:06:16 -0800
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Subject: KASAN: invalid-access Write in enqueue_timer
From:   syzbot <syzbot+95c862be69e37145543f@syzkaller.appspotmail.com>
To:     broonie@kernel.org, catalin.marinas@arm.com, keescook@chromium.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        mark.rutland@arm.com, mbenes@suse.cz,
        syzkaller-bugs@googlegroups.com, will@kernel.org
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Hello,

syzbot found the following issue on:

HEAD commit:    f40ddce8 Linux 5.11
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1395db28d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=494a8e2d9bf09818
dashboard link: https://syzkaller.appspot.com/bug?extid=95c862be69e37145543f
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+95c862be69e37145543f@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: invalid-access in hlist_add_head include/linux/list.h:883 [inline]
BUG: KASAN: invalid-access in enqueue_timer+0x18/0xc0 kernel/time/timer.c:581
Write at addr f4ff0000275dcda0 by task kworker/u4:6/2919
Pointer tag: [f4], memory tag: [fe]

CPU: 1 PID: 2919 Comm: kworker/u4:6 Not tainted 5.11.0-syzkaller #0
Hardware name: linux,dummy-virt (DT)
Workqueue: wg-kex-wg1 wg_packet_handshake_send_worker
Call trace:
 dump_backtrace+0x0/0x1b0 arch/arm64/kernel/stacktrace.c:117
 show_stack+0x18/0x70 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0xd0/0x12c lib/dump_stack.c:120
 print_address_description+0x70/0x29c mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:396 [inline]
 kasan_report+0x134/0x380 mm/kasan/report.c:413
 report_tag_fault arch/arm64/mm/fault.c:311 [inline]
 do_tag_recovery arch/arm64/mm/fault.c:325 [inline]
 __do_kernel_fault+0x178/0x1bc arch/arm64/mm/fault.c:369
 do_bad_area arch/arm64/mm/fault.c:462 [inline]
 do_tag_check_fault+0x74/0x90 arch/arm64/mm/fault.c:717
 do_mem_abort+0x44/0xbc arch/arm64/mm/fault.c:793
 el1_abort+0x40/0x6c arch/arm64/kernel/entry-common.c:118
 el1_sync_handler+0xac/0xd0 arch/arm64/kernel/entry-common.c:209
 el1_sync+0x70/0x100 arch/arm64/kernel/entry.S:656
 hlist_add_head include/linux/list.h:883 [inline]
 enqueue_timer+0x18/0xc0 kernel/time/timer.c:581
 mod_timer+0x14/0x20 kernel/time/timer.c:1106
 mod_peer_timer drivers/net/wireguard/timers.c:37 [inline]
 wg_timers_any_authenticated_packet_traversal+0x68/0x90 drivers/net/wireguard/timers.c:215
 wg_packet_send_handshake_initiation+0xa8/0xe0 drivers/net/wireguard/send.c:36
 wg_packet_handshake_send_worker+0x1c/0x34 drivers/net/wireguard/send.c:51
 process_one_work+0x1d8/0x360 kernel/workqueue.c:2275
 worker_thread+0x70/0x434 kernel/workqueue.c:2421
 kthread+0x174/0x180 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:958

Allocated by task 6247:
 stack_trace_save+0x50/0x80 kernel/stacktrace.c:121
 kasan_save_stack+0x28/0x60 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:401 [inline]
 ____kasan_kmalloc+0xe8/0x160 mm/kasan/common.c:429
 __kasan_kmalloc+0x14/0x20 mm/kasan/common.c:443
 kasan_kmalloc include/linux/kasan.h:219 [inline]
 __kmalloc_node+0x1d0/0x3ac mm/slub.c:4033
 kmalloc_node include/linux/slab.h:575 [inline]
 kvmalloc_node+0x40/0xe0 mm/util.c:587
 kvmalloc include/linux/mm.h:781 [inline]
 kvzalloc include/linux/mm.h:789 [inline]
 alloc_netdev_mqs+0x5c/0x3bc net/core/dev.c:10546
 rtnl_create_link+0xc8/0x2b0 net/core/rtnetlink.c:3171
 __rtnl_newlink+0x5bc/0x800 net/core/rtnetlink.c:3433
 rtnl_newlink+0x70/0xa0 net/core/rtnetlink.c:3491
 rtnetlink_rcv_msg+0x118/0x334 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x5c/0x130 net/netlink/af_netlink.c:2494
 rtnetlink_rcv+0x18/0x2c net/core/rtnetlink.c:5571
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x25c/0x320 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x1d4/0x3e4 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0x54/0x60 net/socket.c:672
 __sys_sendto+0x118/0x14c net/socket.c:1975
 __do_sys_sendto net/socket.c:1987 [inline]
 __se_sys_sendto net/socket.c:1983 [inline]
 __arm64_sys_sendto+0x2c/0x40 net/socket.c:1983
 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:49 [inline]
 el0_svc_common.constprop.0+0x74/0x190 arch/arm64/kernel/syscall.c:159
 do_el0_svc+0x74/0x90 arch/arm64/kernel/syscall.c:198
 el0_svc+0x14/0x20 arch/arm64/kernel/entry-common.c:365
 el0_sync_handler+0x1a4/0x1b0 arch/arm64/kernel/entry-common.c:381
 el0_sync+0x190/0x1c0 arch/arm64/kernel/entry.S:699

Freed by task 24:
 stack_trace_save+0x50/0x80 kernel/stacktrace.c:121
 kasan_save_stack+0x28/0x60 mm/kasan/common.c:38
 kasan_set_track+0x28/0x40 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/hw_tags.c:174
 ____kasan_slab_free.constprop.0+0x184/0x1c0 mm/kasan/common.c:362
 __kasan_slab_free+0x10/0x20 mm/kasan/common.c:369
 kasan_slab_free include/linux/kasan.h:192 [inline]
 slab_free_hook mm/slub.c:1547 [inline]
 slab_free_freelist_hook+0x98/0x18c mm/slub.c:1580
 slab_free mm/slub.c:3143 [inline]
 kfree+0x324/0x4a0 mm/slub.c:4139
 kvfree+0x3c/0x50 mm/util.c:616
 netdev_freemem+0x18/0x2c net/core/dev.c:10500
 netdev_release+0x30/0x44 net/core/net-sysfs.c:1828
 device_release+0x34/0x90 drivers/base/core.c:1980
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x74/0x120 lib/kobject.c:753
 netdev_run_todo+0x2d0/0x37c net/core/dev.c:10356
 rtnl_unlock+0x10/0x20 net/core/rtnetlink.c:112
 default_device_exit_batch+0x168/0x1a0 net/core/dev.c:11220
 ops_exit_list+0x64/0x80 net/core/net_namespace.c:190
 cleanup_net+0x23c/0x410 net/core/net_namespace.c:604
 process_one_work+0x1d8/0x360 kernel/workqueue.c:2275
 worker_thread+0x70/0x434 kernel/workqueue.c:2421
 kthread+0x174/0x180 kernel/kthread.c:292
 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:958

The buggy address belongs to the object at ffff0000275dc000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 3488 bytes inside of
 4096-byte region [ffff0000275dc000, ffff0000275dd000)
The buggy address belongs to the page:
page:0000000040a3fc39 refcount:1 mapcount:0 mapping:0000000000000000 index:0xf4ff0000275dc000 pfn:0x675d8
head:0000000040a3fc39 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x1ffffc000010200(slab|head)
raw: 01ffffc000010200 fffffc00009cb208 fffffc00009ce808 f5ff000004801900
raw: f4ff0000275dc000 0000000000040001 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000275dcb00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff0000275dcc00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>ffff0000275dcd00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
                                                 ^
 ffff0000275dce00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff0000275dcf00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
==================================================================


---
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