syzbot


possible deadlock in hugetlb_vma_lock_read

Status: upstream: reported on 2025/10/09 17:30
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+1ad78f6a1785a2fceb88@syzkaller.appspotmail.com
First crash: 85d, last: 15d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] possible deadlock in hugetlb_vma_lock_read 0 (1) 2025/10/09 17:30

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.0.134/6523 is trying to acquire lock:
ffff88805b9a94e8 (&resv_map->rw_sema){++++}-{4:4}, at: hugetlb_vma_lock_read mm/hugetlb.c:301 [inline]
ffff88805b9a94e8 (&resv_map->rw_sema){++++}-{4:4}, at: hugetlb_vma_lock_read+0xff/0x130 mm/hugetlb.c:292

but task is already holding lock:
ffff88801f6a2578 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}, at: hugetlb_fault+0x2fa/0x1730 mm/hugetlb.c:5998

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
       hugetlb_fault+0x2fa/0x1730 mm/hugetlb.c:5998
       handle_mm_fault+0x95d/0xad0 mm/memory.c:6578
       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+0x64/0xc0 arch/x86/mm/fault.c:1532
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
       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]
       copy_from_user_iter lib/iov_iter.c:67 [inline]
       iterate_ubuf include/linux/iov_iter.h:30 [inline]
       iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
       iterate_and_advance include/linux/iov_iter.h:330 [inline]
       __copy_from_iter lib/iov_iter.c:261 [inline]
       _copy_from_iter+0x355/0x16c0 lib/iov_iter.c:272
       copy_from_iter include/linux/uio.h:228 [inline]
       copy_from_iter_full include/linux/uio.h:245 [inline]
       do_copy_data_nocache net/mptcp/protocol.c:1817 [inline]
       mptcp_sendmsg+0x1046/0x1ee0 net/mptcp/protocol.c:1940
       inet_sendmsg+0x11c/0x140 net/ipv4/af_inet.c:859
       sock_sendmsg_nosec net/socket.c:727 [inline]
       __sock_sendmsg net/socket.c:742 [inline]
       sock_write_iter+0x509/0x610 net/socket.c:1195
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x7d3/0x11d0 fs/read_write.c:686
       ksys_write+0x1f8/0x250 fs/read_write.c:738
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_sock_nested+0x41/0xf0 net/core/sock.c:3780
       lock_sock include/net/sock.h:1700 [inline]
       inet_shutdown+0x67/0x440 net/ipv4/af_inet.c:913
       nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:318
       recv_work+0x66b/0xa70 drivers/block/nbd.c:1021
       process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
       process_scheduled_works kernel/workqueue.c:3340 [inline]
       worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
       kthread+0x3c5/0x780 kernel/kthread.c:463
       ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
       nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
       nbd_queue_rq+0x423/0x12d0 drivers/block/nbd.c:1207
       blk_mq_dispatch_rq_list+0x416/0x1e20 block/blk-mq.c:2138
       __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+0xcbd/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:2376
       blk_mq_dispatch_list+0x514/0x1300 block/blk-mq.c:2939
       blk_mq_flush_plug_list block/blk-mq.c:2987 [inline]
       blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2959
       __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1225
       blk_finish_plug block/blk-core.c:1252 [inline]
       blk_finish_plug block/blk-core.c:1249 [inline]
       __submit_bio+0x542/0x690 block/blk-core.c:651
       __submit_bio_noacct_mq block/blk-core.c:724 [inline]
       submit_bio_noacct_nocheck+0x53d/0xbe0 block/blk-core.c:755
       submit_bio_noacct+0x5bd/0x1f40 block/blk-core.c:879
       submit_bh fs/buffer.c:2829 [inline]
       block_read_full_folio+0x4db/0x850 fs/buffer.c:2461
       filemap_read_folio+0xc8/0x2a0 mm/filemap.c:2496
       do_read_cache_folio+0x266/0x5c0 mm/filemap.c:4096
       read_mapping_folio include/linux/pagemap.h:1017 [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+0x723/0x1520 block/partitions/core.c:693
       blkdev_get_whole+0x187/0x290 block/bdev.c:765
       bdev_open+0x2c7/0xe40 block/bdev.c:974
       blkdev_open+0x34e/0x4f0 block/fops.c:698
       do_dentry_open+0x748/0x1590 fs/open.c:962
       vfs_open+0x82/0x3f0 fs/open.c:1094
       do_open fs/namei.c:4628 [inline]
       path_openat+0x2078/0x3140 fs/namei.c:4787
       do_filp_open+0x20b/0x470 fs/namei.c:4814
       do_sys_openat2+0x121/0x290 fs/open.c:1430
       do_sys_open fs/open.c:1436 [inline]
       __do_sys_openat fs/open.c:1452 [inline]
       __se_sys_openat fs/open.c:1447 [inline]
       __x64_sys_openat+0x174/0x210 fs/open.c:1447
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
       nbd_queue_rq+0xbd/0x12d0 drivers/block/nbd.c:1199
       blk_mq_dispatch_rq_list+0x416/0x1e20 block/blk-mq.c:2138
       __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+0xcbd/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:2376
       blk_mq_dispatch_list+0x514/0x1300 block/blk-mq.c:2939
       blk_mq_flush_plug_list block/blk-mq.c:2987 [inline]
       blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2959
       __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1225
       blk_finish_plug block/blk-core.c:1252 [inline]
       blk_finish_plug block/blk-core.c:1249 [inline]
       __submit_bio+0x542/0x690 block/blk-core.c:651
       __submit_bio_noacct_mq block/blk-core.c:724 [inline]
       submit_bio_noacct_nocheck+0x53d/0xbe0 block/blk-core.c:755
       submit_bio_noacct+0x5bd/0x1f40 block/blk-core.c:879
       submit_bh fs/buffer.c:2829 [inline]
       block_read_full_folio+0x4db/0x850 fs/buffer.c:2461
       filemap_read_folio+0xc8/0x2a0 mm/filemap.c:2496
       do_read_cache_folio+0x266/0x5c0 mm/filemap.c:4096
       read_mapping_folio include/linux/pagemap.h:1017 [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+0x723/0x1520 block/partitions/core.c:693
       blkdev_get_whole+0x187/0x290 block/bdev.c:765
       bdev_open+0x2c7/0xe40 block/bdev.c:974
       blkdev_open+0x34e/0x4f0 block/fops.c:698
       do_dentry_open+0x748/0x1590 fs/open.c:962
       vfs_open+0x82/0x3f0 fs/open.c:1094
       do_open fs/namei.c:4628 [inline]
       path_openat+0x2078/0x3140 fs/namei.c:4787
       do_filp_open+0x20b/0x470 fs/namei.c:4814
       do_sys_openat2+0x121/0x290 fs/open.c:1430
       do_sys_open fs/open.c:1436 [inline]
       __do_sys_openat fs/open.c:1452 [inline]
       __se_sys_openat fs/open.c:1447 [inline]
       __x64_sys_openat+0x174/0x210 fs/open.c:1447
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (set->srcu){.+.+}-{0:0}:
       srcu_lock_sync include/linux/srcu.h:197 [inline]
       __synchronize_srcu+0xa2/0x250 kernel/rcu/srcutree.c:1503
       blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline]
       blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline]
       blk_mq_quiesce_queue block/blk-mq.c:304 [inline]
       blk_mq_quiesce_queue+0x149/0x1b0 block/blk-mq.c:299
       elevator_switch+0x17d/0x7f0 block/elevator.c:576
       elevator_change+0x38b/0x570 block/elevator.c:684
       elevator_set_default+0x2d2/0x390 block/elevator.c:757
       blk_register_queue+0x384/0x4e0 block/blk-sysfs.c:932
       __add_disk+0x74a/0xf00 block/genhd.c:528
       add_disk_fwnode+0x13f/0x5d0 block/genhd.c:597
       add_disk include/linux/blkdev.h:785 [inline]
       nbd_dev_add+0x783/0xbb0 drivers/block/nbd.c:1984
       nbd_init+0x181/0x320 drivers/block/nbd.c:2692
       do_one_initcall+0x123/0x680 init/main.c:1378
       do_initcall_level init/main.c:1440 [inline]
       do_initcalls init/main.c:1456 [inline]
       do_basic_setup init/main.c:1475 [inline]
       kernel_init_freeable+0x5c8/0x920 init/main.c:1688
       kernel_init+0x1c/0x2b0 init/main.c:1578
       ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #3 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
       elevator_change+0x1ed/0x570 block/elevator.c:682
       elv_iosched_store+0x3e8/0x4a0 block/elevator.c:815
       queue_attr_store+0x26b/0x310 block/blk-sysfs.c:859
       sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
       kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352
       iter_file_splice_write+0xa24/0x12b0 fs/splice.c:738
       do_splice_from fs/splice.c:938 [inline]
       direct_splice_actor+0x192/0x6c0 fs/splice.c:1161
       splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105
       do_splice_direct_actor fs/splice.c:1204 [inline]
       do_splice_direct+0x174/0x240 fs/splice.c:1230
       do_sendfile+0xb06/0xe50 fs/read_write.c:1370
       __do_sys_sendfile64 fs/read_write.c:1431 [inline]
       __se_sys_sendfile64 fs/read_write.c:1417 [inline]
       __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->q_usage_counter(io)#66){++++}-{0:0}:
       blk_alloc_queue+0x610/0x750 block/blk-core.c:461
       blk_mq_alloc_queue+0x172/0x280 block/blk-mq.c:4415
       __blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4462
       null_add_dev+0xf2e/0x1eb0 drivers/block/null_blk/main.c:1999
       null_create_dev drivers/block/null_blk/main.c:2097 [inline]
       null_init+0x2c9/0x610 drivers/block/null_blk/main.c:2169
       do_one_initcall+0x123/0x680 init/main.c:1378
       do_initcall_level init/main.c:1440 [inline]
       do_initcalls init/main.c:1456 [inline]
       do_basic_setup init/main.c:1475 [inline]
       kernel_init_freeable+0x5c8/0x920 init/main.c:1688
       kernel_init+0x1c/0x2b0 init/main.c:1578
       ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4301 [inline]
       fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:4315
       might_alloc include/linux/sched/mm.h:317 [inline]
       slab_pre_alloc_hook mm/slub.c:4904 [inline]
       slab_alloc_node mm/slub.c:5239 [inline]
       kmem_cache_alloc_noprof+0x5b/0x770 mm/slub.c:5270
       anon_vma_chain_alloc mm/rmap.c:141 [inline]
       __anon_vma_prepare+0xae/0x5e0 mm/rmap.c:194
       __vmf_anon_prepare+0x11c/0x240 mm/memory.c:3673
       hugetlb_no_page+0x10ae/0x2140 mm/hugetlb.c:5782
       hugetlb_fault+0x5ed/0x1730 mm/hugetlb.c:6035
       handle_mm_fault+0x95d/0xad0 mm/memory.c:6578
       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+0x64/0xc0 arch/x86/mm/fault.c:1532
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
       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:185 [inline]
       _copy_from_user+0x98/0xd0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:223 [inline]
       do_pages_stat+0x240/0x7b0 mm/migrate.c:2509
       kernel_move_pages+0xfc8/0x12f0 mm/migrate.c:2595
       __do_sys_move_pages mm/migrate.c:2606 [inline]
       __se_sys_move_pages mm/migrate.c:2601 [inline]
       __x64_sys_move_pages+0xe0/0x1c0 mm/migrate.c:2601
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&resv_map->rw_sema){++++}-{4:4}:
       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+0x1669/0x2890 kernel/locking/lockdep.c:5237
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825
       down_read+0x9b/0x460 kernel/locking/rwsem.c:1537
       hugetlb_vma_lock_read mm/hugetlb.c:301 [inline]
       hugetlb_vma_lock_read+0xff/0x130 mm/hugetlb.c:292
       hugetlb_fault+0x302/0x1730 mm/hugetlb.c:6005
       handle_mm_fault+0x95d/0xad0 mm/memory.c:6578
       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+0x64/0xc0 arch/x86/mm/fault.c:1532
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
       rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:53
       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:185 [inline]
       _copy_from_user+0x98/0xd0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:223 [inline]
       sctp_getsockopt_local_addrs net/sctp/socket.c:6302 [inline]
       sctp_getsockopt+0x132c/0x7050 net/sctp/socket.c:8169
       do_sock_getsockopt+0x324/0x410 net/socket.c:2383
       __sys_getsockopt+0x123/0x1b0 net/socket.c:2412
       __do_sys_getsockopt net/socket.c:2419 [inline]
       __se_sys_getsockopt net/socket.c:2416 [inline]
       __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2416
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0xf80 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:
  &resv_map->rw_sema --> sk_lock-AF_INET --> &hugetlb_fault_mutex_table[i]

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&hugetlb_fault_mutex_table[i]);
                               lock(sk_lock-AF_INET);
                               lock(&hugetlb_fault_mutex_table[i]);
  rlock(&resv_map->rw_sema);

 *** DEADLOCK ***

3 locks held by syz.0.134/6523:
 #0: ffff888029b28260 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline]
 #0: ffff888029b28260 (sk_lock-AF_INET){+.+.}-{0:0}, at: sctp_getsockopt+0x2d6/0x7050 net/sctp/socket.c:8131
 #1: ffff88807c681bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:410 [inline]
 #1: ffff88807c681bc0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:390 [inline]
 #1: ffff88807c681bc0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x35/0x6e0 mm/mmap_lock.c:450
 #2: ffff88801f6a2578 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}, at: hugetlb_fault+0x2fa/0x1730 mm/hugetlb.c:5998

stack backtrace:
CPU: 0 UID: 0 PID: 6523 Comm: syz.0.134 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x340 kernel/locking/lockdep.c:2043
 check_noncircular+0x146/0x160 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+0x1669/0x2890 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825
 down_read+0x9b/0x460 kernel/locking/rwsem.c:1537
 hugetlb_vma_lock_read mm/hugetlb.c:301 [inline]
 hugetlb_vma_lock_read+0xff/0x130 mm/hugetlb.c:292
 hugetlb_fault+0x302/0x1730 mm/hugetlb.c:6005
 handle_mm_fault+0x95d/0xad0 mm/memory.c:6578
 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+0x64/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:60
Code: 83 f9 08 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 e9 0d 81 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
RSP: 0018:ffffc90018687a60 EFLAGS: 00050246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000008
RDX: fffff520030d0f94 RSI: 0000000000000000 RDI: ffffc90018687c98
RBP: 0000000000000008 R08: 0000000000000001 R09: fffff520030d0f93
R10: ffffc90018687c9f R11: ffff888030ff0b30 R12: 0000000000000000
R13: ffffc90018687c98 R14: 0000000000000000 R15: 1ffff920030d0f5f
 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:185 [inline]
 _copy_from_user+0x98/0xd0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:223 [inline]
 sctp_getsockopt_local_addrs net/sctp/socket.c:6302 [inline]
 sctp_getsockopt+0x132c/0x7050 net/sctp/socket.c:8169
 do_sock_getsockopt+0x324/0x410 net/socket.c:2383
 __sys_getsockopt+0x123/0x1b0 net/socket.c:2412
 __do_sys_getsockopt net/socket.c:2419 [inline]
 __se_sys_getsockopt net/socket.c:2416 [inline]
 __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2416
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f809a98f7c9
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:00007f809b7f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007f809abe5fa0 RCX: 00007f809a98f7c9
RDX: 000000000000006d RSI: 0000000000000084 RDI: 0000000000000004
RBP: 00007f809aa13f91 R08: 0000200000000280 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f809abe6038 R14: 00007f809abe5fa0 R15: 00007ffd0112e738
 </TASK>
netlink: 25 bytes leftover after parsing attributes in process `syz.0.134'.
netlink: 198 bytes leftover after parsing attributes in process `syz.0.134'.
----------------
Code disassembly (best guess):
   0:	83 f9 08             	cmp    $0x8,%ecx
   3:	73 25                	jae    0x2a
   5:	85 c9                	test   %ecx,%ecx
   7:	74 0f                	je     0x18
   9:	8a 06                	mov    (%rsi),%al
   b:	88 07                	mov    %al,(%rdi)
   d:	48 ff c7             	inc    %rdi
  10:	48 ff c6             	inc    %rsi
  13:	48 ff c9             	dec    %rcx
  16:	75 f1                	jne    0x9
  18:	e9 0d 81 04 00       	jmp    0x4812a
  1d:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
  24:	00 00 00 00
  28:	66 90                	xchg   %ax,%ax
* 2a:	48 8b 06             	mov    (%rsi),%rax <-- trapping instruction
  2d:	48 89 07             	mov    %rax,(%rdi)
  30:	48 83 c6 08          	add    $0x8,%rsi
  34:	48 83 c7 08          	add    $0x8,%rdi
  38:	83 e9 08             	sub    $0x8,%ecx
  3b:	74 db                	je     0x18
  3d:	83 f9 08             	cmp    $0x8,%ecx

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/14 13:00 upstream 8f0b4cce4481 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in hugetlb_vma_lock_read
2025/10/11 15:09 upstream 0739473694c4 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in hugetlb_vma_lock_read
2025/10/06 19:04 upstream fd94619c4336 91305dbe .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in hugetlb_vma_lock_read
2025/10/05 17:20 upstream 6093a688a07d 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto possible deadlock in hugetlb_vma_lock_read
* Struck through repros no longer work on HEAD.