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Message-ID: <68dd8f2b.a00a0220.102ee.0063.GAE@google.com>
Date: Wed, 01 Oct 2025 13:29:31 -0700
From: syzbot <syzbot+a2667f4df816b1e2651f@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org,
kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] possible deadlock in l2tp_ip6_sendmsg
Hello,
syzbot found the following issue on:
HEAD commit: 30d4efb2f5a5 Merge tag 'for-linus-6.18-rc1-tag' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13908092580000
kernel config: https://syzkaller.appspot.com/x/.config?x=15ae667b7d4fba35
dashboard link: https://syzkaller.appspot.com/bug?extid=a2667f4df816b1e2651f
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0d17a722ec0e/disk-30d4efb2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f57b31c84a36/vmlinux-30d4efb2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8fafc96499a6/bzImage-30d4efb2.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2667f4df816b1e2651f@...kaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.353/7583 is trying to acquire lock:
ffffffff8e35c620 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:318 [inline]
ffffffff8e35c620 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages+0x162/0x610 mm/page_alloc.c:4916
but task is already holding lock:
ffff888075fc0258 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline]
ffff888075fc0258 (sk_lock-AF_INET6){+.+.}-{0:0}, at: l2tp_ip6_sendmsg+0xf58/0x1e70 net/l2tp/l2tp_ip6.c:652
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #6 (sk_lock-AF_INET6){+.+.}-{0:0}:
lock_sock_nested+0x41/0xf0 net/core/sock.c:3711
lock_sock include/net/sock.h:1669 [inline]
inet_autobind+0x1a/0x1a0 net/ipv4/af_inet.c:178
inet_send_prepare+0x31b/0x530 net/ipv4/af_inet.c:837
inet_sendmsg+0x43/0x140 net/ipv4/af_inet.c:848
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg net/socket.c:729 [inline]
sock_sendmsg+0x37f/0x470 net/socket.c:752
__sock_xmit+0x1e7/0x4f0 drivers/block/nbd.c:574
sock_xmit drivers/block/nbd.c:602 [inline]
nbd_send_cmd+0x8e4/0x1c90 drivers/block/nbd.c:712
nbd_handle_cmd drivers/block/nbd.c:1174 [inline]
nbd_queue_rq+0x940/0x12d0 drivers/block/nbd.c:1204
blk_mq_dispatch_rq_list+0x416/0x1e20 block/blk-mq.c:2120
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcb7/0x15f0 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd8/0x1b0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x239/0x670 block/blk-mq.c:2358
blk_mq_dispatch_list+0x514/0x1310 block/blk-mq.c:2919
blk_mq_flush_plug_list block/blk-mq.c:2967 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2939
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1222
blk_finish_plug block/blk-core.c:1249 [inline]
blk_finish_plug block/blk-core.c:1246 [inline]
__submit_bio+0x545/0x690 block/blk-core.c:651
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x660/0xd30 block/blk-core.c:753
submit_bio_noacct+0xb49/0x1ed0 block/blk-core.c:876
submit_bh fs/buffer.c:2829 [inline]
block_read_full_folio+0x4db/0x850 fs/buffer.c:2461
filemap_read_folio+0xc5/0x2a0 mm/filemap.c:2413
do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3957
read_mapping_folio include/linux/pagemap.h:991 [inline]
read_part_sector+0xd4/0x370 block/partitions/core.c:722
adfspart_check_ICS+0x93/0x940 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x720/0x1520 block/partitions/core.c:693
blkdev_get_whole+0x187/0x290 block/bdev.c:748
bdev_open+0x2c7/0xe40 block/bdev.c:957
blkdev_open+0x34e/0x4f0 block/fops.c:694
do_dentry_open+0x97f/0x1530 fs/open.c:965
vfs_open+0x82/0x3f0 fs/open.c:1095
do_open fs/namei.c:3975 [inline]
path_openat+0x1de4/0x2cb0 fs/namei.c:4134
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
nbd_handle_cmd drivers/block/nbd.c:1140 [inline]
nbd_queue_rq+0x423/0x12d0 drivers/block/nbd.c:1204
blk_mq_dispatch_rq_list+0x416/0x1e20 block/blk-mq.c:2120
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcb7/0x15f0 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd8/0x1b0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x239/0x670 block/blk-mq.c:2358
blk_mq_dispatch_list+0x514/0x1310 block/blk-mq.c:2919
blk_mq_flush_plug_list block/blk-mq.c:2967 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2939
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1222
blk_finish_plug block/blk-core.c:1249 [inline]
blk_finish_plug block/blk-core.c:1246 [inline]
__submit_bio+0x545/0x690 block/blk-core.c:651
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x660/0xd30 block/blk-core.c:753
submit_bio_noacct+0xb49/0x1ed0 block/blk-core.c:876
submit_bh fs/buffer.c:2829 [inline]
block_read_full_folio+0x4db/0x850 fs/buffer.c:2461
filemap_read_folio+0xc5/0x2a0 mm/filemap.c:2413
do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3957
read_mapping_folio include/linux/pagemap.h:991 [inline]
read_part_sector+0xd4/0x370 block/partitions/core.c:722
adfspart_check_ICS+0x93/0x940 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x720/0x1520 block/partitions/core.c:693
blkdev_get_whole+0x187/0x290 block/bdev.c:748
bdev_open+0x2c7/0xe40 block/bdev.c:957
blkdev_open+0x34e/0x4f0 block/fops.c:694
do_dentry_open+0x97f/0x1530 fs/open.c:965
vfs_open+0x82/0x3f0 fs/open.c:1095
do_open fs/namei.c:3975 [inline]
path_openat+0x1de4/0x2cb0 fs/namei.c:4134
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&cmd->lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
nbd_queue_rq+0xbd/0x12d0 drivers/block/nbd.c:1196
blk_mq_dispatch_rq_list+0x416/0x1e20 block/blk-mq.c:2120
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xcb7/0x15f0 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd8/0x1b0 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x239/0x670 block/blk-mq.c:2358
blk_mq_dispatch_list+0x514/0x1310 block/blk-mq.c:2919
blk_mq_flush_plug_list block/blk-mq.c:2967 [inline]
blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2939
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1222
blk_finish_plug block/blk-core.c:1249 [inline]
blk_finish_plug block/blk-core.c:1246 [inline]
__submit_bio+0x545/0x690 block/blk-core.c:651
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x660/0xd30 block/blk-core.c:753
submit_bio_noacct+0xb49/0x1ed0 block/blk-core.c:876
submit_bh fs/buffer.c:2829 [inline]
block_read_full_folio+0x4db/0x850 fs/buffer.c:2461
filemap_read_folio+0xc5/0x2a0 mm/filemap.c:2413
do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3957
read_mapping_folio include/linux/pagemap.h:991 [inline]
read_part_sector+0xd4/0x370 block/partitions/core.c:722
adfspart_check_ICS+0x93/0x940 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x720/0x1520 block/partitions/core.c:693
blkdev_get_whole+0x187/0x290 block/bdev.c:748
bdev_open+0x2c7/0xe40 block/bdev.c:957
blkdev_open+0x34e/0x4f0 block/fops.c:694
do_dentry_open+0x97f/0x1530 fs/open.c:965
vfs_open+0x82/0x3f0 fs/open.c:1095
do_open fs/namei.c:3975 [inline]
path_openat+0x1de4/0x2cb0 fs/namei.c:4134
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (set->srcu){.+.+}-{0:0}:
srcu_lock_sync include/linux/srcu.h:173 [inline]
__synchronize_srcu+0xa1/0x290 kernel/rcu/srcutree.c:1429
blk_mq_wait_quiesce_done block/blk-mq.c:283 [inline]
blk_mq_wait_quiesce_done block/blk-mq.c:280 [inline]
blk_mq_quiesce_queue block/blk-mq.c:303 [inline]
blk_mq_quiesce_queue+0x149/0x1b0 block/blk-mq.c:298
elevator_switch+0x17d/0x810 block/elevator.c:588
elevator_change+0x391/0x580 block/elevator.c:690
elevator_set_default+0x2e9/0x380 block/elevator.c:766
blk_register_queue+0x384/0x4e0 block/blk-sysfs.c:904
__add_disk+0x74a/0xf00 block/genhd.c:528
add_disk_fwnode+0x13f/0x5d0 block/genhd.c:597
add_disk include/linux/blkdev.h:774 [inline]
nbd_dev_add+0x783/0xbb0 drivers/block/nbd.c:1973
nbd_init+0x181/0x320 drivers/block/nbd.c:2680
do_one_initcall+0x120/0x6e0 init/main.c:1271
do_initcall_level init/main.c:1333 [inline]
do_initcalls init/main.c:1349 [inline]
do_basic_setup init/main.c:1368 [inline]
kernel_init_freeable+0x5c2/0x910 init/main.c:1581
kernel_init+0x1c/0x2b0 init/main.c:1471
ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #2 (&q->elevator_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760
elevator_change+0x17d/0x580 block/elevator.c:688
elv_iosched_store+0x315/0x3c0 block/elevator.c:823
queue_attr_store+0x26b/0x310 block/blk-sysfs.c:831
sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3ac/0x570 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#62){++++}-{0:0}:
blk_alloc_queue+0x619/0x760 block/blk-core.c:461
blk_mq_alloc_queue+0x172/0x280 block/blk-mq.c:4400
__blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4447
nbd_dev_add+0x492/0xbb0 drivers/block/nbd.c:1943
nbd_init+0x181/0x320 drivers/block/nbd.c:2680
do_one_initcall+0x120/0x6e0 init/main.c:1271
do_initcall_level init/main.c:1333 [inline]
do_initcalls init/main.c:1349 [inline]
do_basic_setup init/main.c:1368 [inline]
kernel_init_freeable+0x5c2/0x910 init/main.c:1581
kernel_init+0x1c/0x2b0 init/main.c:1471
ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
__fs_reclaim_acquire mm/page_alloc.c:4234 [inline]
fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:4248
might_alloc include/linux/sched/mm.h:318 [inline]
prepare_alloc_pages+0x162/0x610 mm/page_alloc.c:4916
__alloc_frozen_pages_noprof+0x18b/0x23f0 mm/page_alloc.c:5137
alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2507
pagetable_alloc_noprof include/linux/mm.h:2881 [inline]
pmd_alloc_one_noprof include/asm-generic/pgalloc.h:142 [inline]
__pmd_alloc+0x3b/0x930 mm/memory.c:6450
pmd_alloc include/linux/mm.h:2844 [inline]
__handle_mm_fault+0xa06/0x2a50 mm/memory.c:6155
handle_mm_fault+0x589/0xd10 mm/memory.c:6364
do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:68
copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline]
_inline_copy_from_user include/linux/uaccess.h:178 [inline]
_copy_from_user+0x98/0xd0 lib/usercopy.c:18
copy_from_user include/linux/uaccess.h:212 [inline]
csum_and_copy_from_user include/net/checksum.h:31 [inline]
copy_from_user_iter_csum net/core/skbuff.c:7323 [inline]
iterate_ubuf include/linux/iov_iter.h:30 [inline]
iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
csum_and_copy_from_iter_full+0x21a/0x1f90 net/core/skbuff.c:7335
ip_generic_getfrag+0x170/0x270 net/ipv4/ip_output.c:940
__ip6_append_data+0x2e36/0x4750 net/ipv6/ip6_output.c:1706
ip6_append_data+0x1bd/0x4c0 net/ipv6/ip6_output.c:1860
l2tp_ip6_sendmsg+0xfe6/0x1e70 net/l2tp/l2tp_ip6.c:654
inet_sendmsg+0x11c/0x140 net/ipv4/af_inet.c:851
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg net/socket.c:729 [inline]
__sys_sendto+0x43c/0x520 net/socket.c:2231
__do_sys_sendto net/socket.c:2238 [inline]
__se_sys_sendto net/socket.c:2234 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2234
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
fs_reclaim --> &nsock->tx_lock --> sk_lock-AF_INET6
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sk_lock-AF_INET6);
lock(&nsock->tx_lock);
lock(sk_lock-AF_INET6);
lock(fs_reclaim);
*** DEADLOCK ***
2 locks held by syz.1.353/7583:
#0: ffff888075fc0258 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline]
#0: ffff888075fc0258 (sk_lock-AF_INET6){+.+.}-{0:0}, at: l2tp_ip6_sendmsg+0xf58/0x1e70 net/l2tp/l2tp_ip6.c:652
#1: ffff88807ca2d7e0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:472 [inline]
#1: ffff88807ca2d7e0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:277 [inline]
#1: ffff88807ca2d7e0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x35/0x6e0 mm/mmap_lock.c:337
stack backtrace:
CPU: 1 UID: 0 PID: 7583 Comm: syz.1.353 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2043
check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
__fs_reclaim_acquire mm/page_alloc.c:4234 [inline]
fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:4248
might_alloc include/linux/sched/mm.h:318 [inline]
prepare_alloc_pages+0x162/0x610 mm/page_alloc.c:4916
__alloc_frozen_pages_noprof+0x18b/0x23f0 mm/page_alloc.c:5137
alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2507
pagetable_alloc_noprof include/linux/mm.h:2881 [inline]
pmd_alloc_one_noprof include/asm-generic/pgalloc.h:142 [inline]
__pmd_alloc+0x3b/0x930 mm/memory.c:6450
pmd_alloc include/linux/mm.h:2844 [inline]
__handle_mm_fault+0xa06/0x2a50 mm/memory.c:6155
handle_mm_fault+0x589/0xd10 mm/memory.c:6364
do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:74
Code: 1e 04 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb c5 <f3> a4 e9 4f 1e 04 00 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48
RSP: 0018:ffffc9000e67f648 EFLAGS: 00050202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000402
RDX: ffffed100f846e89 RSI: 0000000000000000 RDI: ffff88807c237044
RBP: 0000000000000402 R08: 0000000000000001 R09: ffffed100f846e88
R10: ffff88807c237445 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88807c237044 R14: 0000000000000000 R15: 0000000000000402
copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline]
_inline_copy_from_user include/linux/uaccess.h:178 [inline]
_copy_from_user+0x98/0xd0 lib/usercopy.c:18
copy_from_user include/linux/uaccess.h:212 [inline]
csum_and_copy_from_user include/net/checksum.h:31 [inline]
copy_from_user_iter_csum net/core/skbuff.c:7323 [inline]
iterate_ubuf include/linux/iov_iter.h:30 [inline]
iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
csum_and_copy_from_iter_full+0x21a/0x1f90 net/core/skbuff.c:7335
ip_generic_getfrag+0x170/0x270 net/ipv4/ip_output.c:940
__ip6_append_data+0x2e36/0x4750 net/ipv6/ip6_output.c:1706
ip6_append_data+0x1bd/0x4c0 net/ipv6/ip6_output.c:1860
l2tp_ip6_sendmsg+0xfe6/0x1e70 net/l2tp/l2tp_ip6.c:654
inet_sendmsg+0x11c/0x140 net/ipv4/af_inet.c:851
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg net/socket.c:729 [inline]
__sys_sendto+0x43c/0x520 net/socket.c:2231
__do_sys_sendto net/socket.c:2238 [inline]
__se_sys_sendto net/socket.c:2234 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2234
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7dbc78eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7dbd580038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f7dbc9e5fa0 RCX: 00007f7dbc78eec9
RDX: 0000000000000402 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f7dbc811f91 R08: 0000200000000000 R09: 000000000000001c
R10: 000000000000fe80 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7dbc9e6038 R14: 00007f7dbc9e5fa0 R15: 00007ffc5c9749e8
</TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 04 00 add $0x0,%al
2: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
9: 00 00 00 00
d: 66 90 xchg %ax,%ax
f: 48 8b 06 mov (%rsi),%rax
12: 48 89 07 mov %rax,(%rdi)
15: 48 83 c6 08 add $0x8,%rsi
19: 48 83 c7 08 add $0x8,%rdi
1d: 83 e9 08 sub $0x8,%ecx
20: 74 db je 0xfffffffd
22: 83 f9 08 cmp $0x8,%ecx
25: 73 e8 jae 0xf
27: eb c5 jmp 0xffffffee
* 29: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
2b: e9 4f 1e 04 00 jmp 0x41e7f
30: 48 8b 06 mov (%rsi),%rax
33: 48 89 07 mov %rax,(%rdi)
36: 48 8d 47 08 lea 0x8(%rdi),%rax
3a: 48 83 e0 f8 and $0xfffffffffffffff8,%rax
3e: 48 rex.W
---
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