bisecting cause commit starting from d3432bf10f17bd8ef7d6ca0a268f63bfb0c3d372
building syzkaller on 6972b10616d785401dea17cec890cca8916424a7
testing commit d3432bf10f17bd8ef7d6ca0a268f63bfb0c3d372
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 8f2c636702c5fda1b8929f0a08bfdc12e0f53315ffe17e755d0c5d0d86fbc313
run #0: crashed: KASAN: invalid-free in bdev_free_inode
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
reproducer seems to be flaky
testing release v5.13
testing commit 62fb9874f5da54fdb243003b386128037319b219
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 909f5b513362d755e99068620c19525cb2afd91ca8725228219fd46574a48866
run #0: crashed: BUG: sleeping function called from invalid context in lock_sock_nested
run #1: OK
run #2: crashed: BUG: spinlock bad magic in synchronize_srcu
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
testing release v5.12
testing commit 9f4ad9e425a1d3b6a34617b8ea226d56a119a717
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: bb4e26dd8f4a005b0fd76547575ef29621d4d502b5251ddaf0a5696974104629
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
testing release v5.11
testing commit f40ddce88593482919761f74910f42f4b84c004b
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 3222e6ed80513dd888ba5df1ed0bb0fed90b38311471a07f8ebfef14f678fd42
all runs: OK
# git bisect start 9f4ad9e425a1d3b6a34617b8ea226d56a119a717 f40ddce88593482919761f74910f42f4b84c004b
Bisecting: 6798 revisions left to test after this (roughly 13 steps)
[d99676af540c2dc829999928fb81c58c80a1dce4] Merge tag 'drm-next-2021-02-19' of git://anongit.freedesktop.org/drm/drm

testing commit d99676af540c2dc829999928fb81c58c80a1dce4
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: f0c248143fbb01c9220d7d749817b4bd905f8d78b2dcc1efd4218ef484b8cf57
run #0: basic kernel testing failed: WARNING in kvm_wait
run #1: basic kernel testing failed: WARNING in kvm_wait
run #2: basic kernel testing failed: WARNING in kvm_wait
run #3: crashed: WARNING in kvm_wait
run #4: crashed: WARNING in kvm_wait
run #5: crashed: WARNING in kvm_wait
run #6: crashed: WARNING in kvm_wait
run #7: crashed: WARNING in kvm_wait
run #8: crashed: WARNING in kvm_wait
run #9: crashed: WARNING in kvm_wait
run #10: OK
run #11: crashed: WARNING in kvm_wait
run #12: OK
run #13: boot failed: WARNING in kvm_wait
run #14: boot failed: WARNING in kvm_wait
run #15: boot failed: WARNING in kvm_wait
run #16: boot failed: WARNING in kvm_wait
run #17: boot failed: WARNING in kvm_wait
run #18: boot failed: WARNING in kvm_wait
run #19: boot failed: WARNING in kvm_wait
# git bisect bad d99676af540c2dc829999928fb81c58c80a1dce4
Bisecting: 3717 revisions left to test after this (roughly 12 steps)
[f9d58de23152f2c16f326d7e014cfa2933b00304] Merge tag 'affs-for-5.12-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

testing commit f9d58de23152f2c16f326d7e014cfa2933b00304
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: a6431cb265fb2e1799b1881f6872b94bbbc521195447951498ba672474e46152
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: crashed: BUG: spinlock bad magic in synchronize_srcu
run #2: OK
run #3: crashed: BUG: spinlock bad magic in synchronize_srcu
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad f9d58de23152f2c16f326d7e014cfa2933b00304
Bisecting: 1819 revisions left to test after this (roughly 11 steps)
[b8af417e4d93caeefb89bbfbd56ec95dedd8dab5] Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

testing commit b8af417e4d93caeefb89bbfbd56ec95dedd8dab5
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 3f8726e045eba6fa894dc915e1eeab5d19ffdc3806ecdd036d97eec23261dba3
all runs: OK
# git bisect good b8af417e4d93caeefb89bbfbd56ec95dedd8dab5
Bisecting: 948 revisions left to test after this (roughly 10 steps)
[82851fce6107d5a3e66d95aee2ae68860a732703] Merge tag 'arm-dt-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

testing commit 82851fce6107d5a3e66d95aee2ae68860a732703
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: b9a00e74743c5d1183376340931fa17aac7bac4c9bf5dc13799d9f4e5d0ae626
all runs: OK
# git bisect good 82851fce6107d5a3e66d95aee2ae68860a732703
Bisecting: 382 revisions left to test after this (roughly 9 steps)
[780607b9731feef575514108fc7956c54180f16e] Merge tag 'usb-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

testing commit 780607b9731feef575514108fc7956c54180f16e
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: a48442f03d928928e1f63065443ebd922d6cd85c10fd7a7dba4dadf044ffd127
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 780607b9731feef575514108fc7956c54180f16e
Bisecting: 266 revisions left to test after this (roughly 8 steps)
[c85bfed171aaa91a32dcecd7962a4c880bf9d0ab] Merge tag 'usb-serial-5.12-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next

testing commit c85bfed171aaa91a32dcecd7962a4c880bf9d0ab
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 3c1fa828fb9272ca4e4f4ca4bb54cd54b4245860693ec92acf79333dd369be4e
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad c85bfed171aaa91a32dcecd7962a4c880bf9d0ab
Bisecting: 152 revisions left to test after this (roughly 7 steps)
[29b01295a829fba7399ee84afff4e64660e49f04] usb: typec: Add typec_partner_set_pd_revision

testing commit 29b01295a829fba7399ee84afff4e64660e49f04
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 231ecd3adfcedcaa5b35b696a08365875486e1bad268a3ef0d8c5554470dff08
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 29b01295a829fba7399ee84afff4e64660e49f04
Bisecting: 72 revisions left to test after this (roughly 6 steps)
[c86cad04dcc8cc07e0befece5e87175c5c71dd4c] drivers/usb/gadget/udc: Assign boolean values to a bool variable

testing commit c86cad04dcc8cc07e0befece5e87175c5c71dd4c
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: b02539a5da6af46197b5a42d7469498d184df6318e90e36e88c490ee036ba380
all runs: OK
# git bisect good c86cad04dcc8cc07e0befece5e87175c5c71dd4c
Bisecting: 36 revisions left to test after this (roughly 5 steps)
[7cbcd008e104d16849e5054e69f0a3d55eaeb664] usb: typec: tcpci_maxim: add terminating newlines to logging

testing commit 7cbcd008e104d16849e5054e69f0a3d55eaeb664
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 4415180c4cfd427aacebf232d2e5ce0eaf08d4af4d25d2e4dbd0cfed5e8fc9d4
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 7cbcd008e104d16849e5054e69f0a3d55eaeb664
Bisecting: 17 revisions left to test after this (roughly 4 steps)
[ead4c124852e66b6aa033e34cf9c4f08d40aeffc] usb: gadget: Introduce udc_set_ssp_rate() for SSP

testing commit ead4c124852e66b6aa033e34cf9c4f08d40aeffc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 29f36093f0774c0d35fd59a7d7433e44cf4f6696eb557a783e0687725eb4e88d
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: crashed: BUG: spinlock bad magic in synchronize_srcu
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad ead4c124852e66b6aa033e34cf9c4f08d40aeffc
Bisecting: 8 revisions left to test after this (roughly 3 steps)
[d93b29c8097144d9911ad0116610d971937748a8] dt-bindings: usb: convert mediatek, mtk-xhci.txt to YAML schema

testing commit d93b29c8097144d9911ad0116610d971937748a8
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 2558b9e19756e7ead20f8fdb24b52019df2f1352a3dee48f0ed8aba64a5758a5
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad d93b29c8097144d9911ad0116610d971937748a8
Bisecting: 4 revisions left to test after this (roughly 2 steps)
[f08fc2c30e7806443143db16ac1457145d39b7dd] usb: dwc3: pci: add support for the Intel Alder Lake-P

testing commit f08fc2c30e7806443143db16ac1457145d39b7dd
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 54202e38b2843dd7e134d475023f15b89923cc996318c61c27843f49fb62b55a
all runs: OK
# git bisect good f08fc2c30e7806443143db16ac1457145d39b7dd
Bisecting: 2 revisions left to test after this (roughly 1 step)
[23bf6fc7046c8c694ff774f0532329dd78efe0a2] dt-bindings: usb: convert usb-device.txt to YAML schema

testing commit 23bf6fc7046c8c694ff774f0532329dd78efe0a2
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 2558b9e19756e7ead20f8fdb24b52019df2f1352a3dee48f0ed8aba64a5758a5
run #0: OK
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: crashed: BUG: spinlock bad magic in synchronize_srcu
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 23bf6fc7046c8c694ff774f0532329dd78efe0a2
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[63d152149b2d0860ccf8c4e6596b6175b2b7ace6] usb: gadget: u_ether: support configuring interface names.

testing commit 63d152149b2d0860ccf8c4e6596b6175b2b7ace6
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 2558b9e19756e7ead20f8fdb24b52019df2f1352a3dee48f0ed8aba64a5758a5
run #0: crashed: BUG: spinlock bad magic in synchronize_srcu
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 63d152149b2d0860ccf8c4e6596b6175b2b7ace6
63d152149b2d0860ccf8c4e6596b6175b2b7ace6 is the first bad commit
commit 63d152149b2d0860ccf8c4e6596b6175b2b7ace6
Author: Lorenzo Colitti <lorenzo@google.com>
Date:   Thu Jan 14 08:42:22 2021 +0900

    usb: gadget: u_ether: support configuring interface names.
    
    This patch allows the administrator to configure the interface
    name of a function using u_ether (e.g., eem, ncm, rndis).
    
    Currently, all such interfaces, regardless of function type, are
    always called usb0, usb1, etc. This makes it very cumbersome to
    use more than one such type at a time, because userspace cannnot
    easily tell the interfaces apart and apply the right
    configuration to each one. Interface renaming in userspace based
    on driver doesn't help, because the interfaces all have the same
    driver. Without this patch, doing this require hacks/workarounds
    such as setting fixed MAC addresses on the functions, and then
    renaming by MAC address, or scraping configfs after each
    interface is created to find out what it is.
    
    Setting the interface name is done by writing to the same
    "ifname" configfs attribute that reports the interface name after
    the function is bound. The write must contain an interface
    pattern such as "usb%d" (which will cause the net core to pick
    the next available interface name starting with "usb").
    This patch does not allow writing an exact interface name (as
    opposed to a pattern) because if the interface already exists at
    bind time, the bind will fail and the whole gadget will fail to
    activate. This could be allowed in a future patch.
    
    For compatibility with current userspace, when reading an ifname
    that has not currently been set, the result is still "(unnamed
    net_device)". Once a write to ifname happens, then reading ifname
    will return whatever was last written.
    
    Tested by configuring an rndis function and an ncm function on
    the same gadget, and writing "rndis%d" to ifname on the rndis
    function and "ncm%d" to ifname on the ncm function. When the
    gadget was bound, the rndis interface was rndis0 and the ncm
    interface was ncm0.
    
    Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
    Link: https://lore.kernel.org/r/20210113234222.3272933-1-lorenzo@google.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 Documentation/usb/gadget-testing.rst           | 30 +++++++++++------------
 drivers/usb/gadget/function/u_ether.c          | 33 +++++++++++++++++++++++++-
 drivers/usb/gadget/function/u_ether.h          | 12 ++++++++++
 drivers/usb/gadget/function/u_ether_configfs.h | 15 +++++++++++-
 4 files changed, 73 insertions(+), 17 deletions(-)

culprit signature: 2558b9e19756e7ead20f8fdb24b52019df2f1352a3dee48f0ed8aba64a5758a5
parent  signature: 54202e38b2843dd7e134d475023f15b89923cc996318c61c27843f49fb62b55a
Reproducer flagged being flaky
revisions tested: 18, total time: 4h45m58.713757584s (build: 1h54m54.15261697s, test: 2h48m52.368013388s)
first bad commit: 63d152149b2d0860ccf8c4e6596b6175b2b7ace6 usb: gadget: u_ether: support configuring interface names.
recipients (to): ["balbi@kernel.org" "corbet@lwn.net" "gregkh@linuxfoundation.org" "gregkh@linuxfoundation.org" "linux-doc@vger.kernel.org" "linux-usb@vger.kernel.org" "lorenzo@google.com"]
recipients (cc): ["linux-kernel@vger.kernel.org" "lorenzo@google.com" "manish.narani@xilinx.com" "maze@google.com"]
crash: BUG: spinlock bad magic in synchronize_srcu
BUG: spinlock bad magic on CPU#0, syz-executor.5/1594
 lock: 0xffff8880b9e00040, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 0 PID: 1594 Comm: syz-executor.5 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x9a/0xcc lib/dump_stack.c:120
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x216/0x2b0 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline]
 _raw_spin_lock_irqsave+0x41/0x50 kernel/locking/spinlock.c:159
 srcu_might_be_idle kernel/rcu/srcutree.c:772 [inline]
 synchronize_srcu+0x4f/0x1c0 kernel/rcu/srcutree.c:999
 blk_mq_quiesce_queue+0xfc/0x190 block/blk-mq.c:233
 elevator_init_mq+0x248/0x350 block/elevator.c:682
 __device_add_disk+0x700/0x1020 block/genhd.c:711
 add_disk include/linux/genhd.h:241 [inline]
 nbd_dev_add+0x661/0x850 drivers/block/nbd.c:1731
 nbd_genl_connect+0x408/0x11e0 drivers/block/nbd.c:1841
 genl_family_rcv_msg_doit+0x1e4/0x2f0 net/netlink/genetlink.c:739
 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
 genl_rcv_msg+0x27d/0x490 net/netlink/genetlink.c:800
 netlink_rcv_skb+0x118/0x370 net/netlink/af_netlink.c:2494
 genl_rcv+0x1f/0x30 net/netlink/genetlink.c:811
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x42e/0x700 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x70e/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xab/0xe0 net/socket.c:672
 ____sys_sendmsg+0x5bf/0x7a0 net/socket.c:2345
 ___sys_sendmsg+0xd3/0x150 net/socket.c:2399
 __sys_sendmsg+0xb2/0x140 net/socket.c:2432
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb30a5e9188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000020000540 RDI: 0000000000000005
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007ffd8803d4cf R14: 00007fb30a5e9300 R15: 0000000000022000
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 1594 Comm: syz-executor.5 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rcu_segcblist_enqueue+0x90/0xf0 kernel/rcu/rcu_segcblist.c:250
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4e 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 20 48 89 ea 48 c1 ea 03 <80> 3c 02 00 75 21 48 89 75 00 48 89 73 20 48 83 c4 08 5b 5d c3 48
RSP: 0018:ffffc90002807128 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880b9e00080 RCX: ffffffff8151dd30
RDX: 0000000000000000 RSI: ffffc90002807210 RDI: ffff8880b9e000a0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52000500e17 R11: 6637303030302052 R12: ffffc90002807210
R13: 0000000000000000 R14: ffff8880b9e00080 R15: ffff8880b9e00040
FS:  00007fb30a5e9700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2de49d8108 CR3: 0000000098651000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __call_srcu+0x193/0xc50 kernel/rcu/srcutree.c:859
 __synchronize_srcu+0x128/0x220 kernel/rcu/srcutree.c:923
 blk_mq_quiesce_queue+0xfc/0x190 block/blk-mq.c:233
 elevator_init_mq+0x248/0x350 block/elevator.c:682
 __device_add_disk+0x700/0x1020 block/genhd.c:711
 add_disk include/linux/genhd.h:241 [inline]
 nbd_dev_add+0x661/0x850 drivers/block/nbd.c:1731
 nbd_genl_connect+0x408/0x11e0 drivers/block/nbd.c:1841
 genl_family_rcv_msg_doit+0x1e4/0x2f0 net/netlink/genetlink.c:739
 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
 genl_rcv_msg+0x27d/0x490 net/netlink/genetlink.c:800
 netlink_rcv_skb+0x118/0x370 net/netlink/af_netlink.c:2494
 genl_rcv+0x1f/0x30 net/netlink/genetlink.c:811
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x42e/0x700 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x70e/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xab/0xe0 net/socket.c:672
 ____sys_sendmsg+0x5bf/0x7a0 net/socket.c:2345
 ___sys_sendmsg+0xd3/0x150 net/socket.c:2399
 __sys_sendmsg+0xb2/0x140 net/socket.c:2432
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb30a5e9188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000020000540 RDI: 0000000000000005
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007ffd8803d4cf R14: 00007fb30a5e9300 R15: 0000000000022000
Modules linked in:
---[ end trace f185a4871ab85c62 ]---
RIP: 0010:rcu_segcblist_enqueue+0x90/0xf0 kernel/rcu/rcu_segcblist.c:250
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4e 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 20 48 89 ea 48 c1 ea 03 <80> 3c 02 00 75 21 48 89 75 00 48 89 73 20 48 83 c4 08 5b 5d c3 48
RSP: 0018:ffffc90002807128 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880b9e00080 RCX: ffffffff8151dd30
RDX: 0000000000000000 RSI: ffffc90002807210 RDI: ffff8880b9e000a0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52000500e17 R11: 6637303030302052 R12: ffffc90002807210
R13: 0000000000000000 R14: ffff8880b9e00080 R15: ffff8880b9e00040
FS:  00007fb30a5e9700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2de49d8108 CR3: 0000000098651000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 7 bytes skipped:
   0:	df 48 89             	fisttps -0x77(%rax)
   3:	fa                   	cli
   4:	48 c1 ea 03          	shr    $0x3,%rdx
   8:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   c:	75 4e                	jne    0x5c
   e:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  15:	fc ff df
  18:	48 8b 6b 20          	mov    0x20(%rbx),%rbp
  1c:	48 89 ea             	mov    %rbp,%rdx
  1f:	48 c1 ea 03          	shr    $0x3,%rdx
* 23:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  27:	75 21                	jne    0x4a
  29:	48 89 75 00          	mov    %rsi,0x0(%rbp)
  2d:	48 89 73 20          	mov    %rsi,0x20(%rbx)
  31:	48 83 c4 08          	add    $0x8,%rsp
  35:	5b                   	pop    %rbx
  36:	5d                   	pop    %rbp
  37:	c3                   	retq
  38:	48                   	rex.W