Created attachment 1140990 [details]
File: dmesg

Description of problem:
Using btrfs send/receive to send a snapshot from a btrfs partition mounted as read-only. The resulting snapshot was ok and btrfs check on the destination didn't complain.

Version-Release number of selected component:
kernel

Additional info:
reporter:       libreport-2.6.4
cmdline:        BOOT_IMAGE=/vmlinuz-4.4.6-300.fc23.x86_64 root=UUID=07a08b80-ab49-4852-aec7-c50951cc3968 ro rootflags=subvol=root rhgb quiet mce=ignore_ce LANG=en_US.UTF-8
kernel:         4.4.6-300.fc23.x86_64
runlevel:       N 5
type:           Kerneloops

Truncated backtrace:
WARNING: CPU: 3 PID: 9388 at fs/btrfs/send.c:5962 btrfs_ioctl_send+0x6c5/0x11e0 [btrfs]()
Modules linked in: xfs libcrc32c rfcomm fuse hidp cmac ccm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun nf_conntrack_tftp nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ftp ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_filter ebtable_nat ebtable_broute bridge ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_security ip6table_raw ip6table_mangle ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_security iptable_raw iptable_mangle bnep intel_rapl iosf_mbi x86_pkg_temp_thermal arc4 coretemp kvm_intel kvm vfat fat irqbypass iTCO_wdt crct10dif_pclmul iTCO_vendor_support crc32_pclmul iwlmvm mac80211 joydev snd_hda_codec_realtek i2c_i801 snd_hda_codec_hdmi
 snd_hda_codec_generic ses iwlwifi enclosure uvcvideo snd_hda_intel videobuf2_vmalloc snd_hda_codec videobuf2_memops btusb cfg80211 videobuf2_v4l2 btrtl btbcm btintel rtsx_pci_ms videobuf2_core v4l2_common lpc_ich memstick videodev bluetooth snd_hda_core mei_me mei shpchp media snd_hwdep snd_seq snd_seq_device snd_pcm wmi thinkpad_acpi snd_timer rfkill snd soundcore tpm_tis tpm nfsd auth_rpcgss nfs_acl lockd binfmt_misc grace sunrpc btrfs xor 8021q garp stp llc mrp i915 rtsx_pci_sdmmc mmc_core raid6_pq i2c_algo_bit drm_kms_helper crc32c_intel drm serio_raw e1000e rtsx_pci ptp pps_core fjes video uas usb_storage i2c_dev
CPU: 3 PID: 9388 Comm: btrfs Not tainted 4.4.6-300.fc23.x86_64 #1
Hardware name: LENOVO 20AR001ERI/20AR001ERI, BIOS GJET86WW (2.36 ) 12/04/2015
 0000000000000286 00000000c73ba98e ffff8801787afbf8 ffffffff813b542e
 0000000000000000 ffffffffa03b9a55 ffff8801787afc30 ffffffff810a40f2
 00007fffc654a470 ffff8800b6106000 00007fffc654a470 ffff8802d5973090
Call Trace:
 [<ffffffff813b542e>] dump_stack+0x63/0x85
 [<ffffffff810a40f2>] warn_slowpath_common+0x82/0xc0
 [<ffffffff810a423a>] warn_slowpath_null+0x1a/0x20
 [<ffffffffa03a9175>] btrfs_ioctl_send+0x6c5/0x11e0 [btrfs]
 [<ffffffff811b6cd3>] ? __alloc_pages_nodemask+0x1d3/0xbc0
 [<ffffffff8133792b>] ? security_file_open+0x8b/0x90
 [<ffffffffa0370a52>] btrfs_ioctl+0x2a2/0x2e60 [btrfs]
 [<ffffffff810d4c0c>] ? __enqueue_entity+0x6c/0x70
 [<ffffffff810dabc2>] ? enqueue_entity+0x3a2/0xc90
 [<ffffffff813c9ea5>] ? find_next_bit+0x15/0x20
 [<ffffffff813b5191>] ? cpumask_next_and+0x31/0x50
 [<ffffffff810db559>] ? enqueue_task_fair+0xa9/0x8f0
 [<ffffffff8133fc9c>] ? selinux_file_ioctl+0x10c/0x1c0
 [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480
 [<ffffffff81337553>] ? security_file_ioctl+0x43/0x60
 [<ffffffff812414a9>] SyS_ioctl+0x79/0x90
 [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71

*********** MASS BUG UPDATE **************
 
We apologize for the inconvenience.  There is a large number of bugs to go through and several of them have gone stale.  Due to this, we are doing a mass bug update across all of the Fedora 23 kernel bugs.
 
Fedora 23 has now been rebased to 4.7.4-100.fc23.  Please test this kernel update (or newer) and let us know if you issue has been resolved or if it is still present with the newer kernel.
 
If you have moved on to Fedora 24 or 25, and are still experiencing this issue, please change the version to Fedora 24 or 25.
 
If you experience different issues, please open a new bug report for those.

I don't have access to the offending filesystem anymore, in order to the with the latest update of Fedora 23.
Other btrfs filesystems that I have access to don't experience this bug.

Thanks for letting us know. Given the reports were on an older version of the kernel, I'm going to close this bug for now. It can be reopened if the problem shows up again.