==================================================================
BUG: KASAN: use-after-free in copy_page_from_iter_atomic+0x97c/0x1228 lib/iov_iter.c:980
Read of size 4096 at addr ffff0000ec5f1000 by task kworker/u4:2/148

CPU: 1 PID: 148 Comm: kworker/u4:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Workqueue: loop0 loop_workfn
Call trace:
 dump_backtrace+0x0/0x458 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x78/0x30c mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xec/0x158 mm/kasan/report.c:451
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x268/0x2a0 mm/kasan/generic.c:189
 memcpy+0x90/0xe8 mm/kasan/shadow.c:65
 copy_page_from_iter_atomic+0x97c/0x1228 lib/iov_iter.c:980
 generic_perform_write+0x27c/0x490 mm/filemap.c:3793
 __generic_file_write_iter+0x23c/0x44c mm/filemap.c:3912
 generic_file_write_iter+0xb0/0x1b4 mm/filemap.c:3944
 do_iter_readv_writev+0x3a4/0x508 fs/read_write.c:-1
 do_iter_write+0x1b8/0x640 fs/read_write.c:855
 vfs_iter_write+0x88/0xac fs/read_write.c:896
 lo_write_bvec+0x368/0xa38 drivers/block/loop.c:316
 lo_write_simple drivers/block/loop.c:338 [inline]
 do_req_filebacked drivers/block/loop.c:656 [inline]
 loop_handle_cmd drivers/block/loop.c:2235 [inline]
 loop_process_work+0x1b68/0x22f4 drivers/block/loop.c:2275
 loop_workfn+0x48/0x58 drivers/block/loop.c:2299
 process_one_work+0x7a4/0x1178 kernel/workqueue.c:2310
 worker_thread+0x8fc/0x103c kernel/workqueue.c:2457
 kthread+0x37c/0x460 kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:856

The buggy address belongs to the page:
page:000000008b4c9a9f refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12c5f1
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003a6f988 fffffc0003b12c08 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ec5f0f00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000ec5f0f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000ec5f1000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000ec5f1080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000ec5f1100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bond: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_team: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_vlan: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_vlan: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vlan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vlan1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macvlan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macvlan1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_macvtap: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macsec0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready