Hi all,
I just tried to unload loop to change the max_part parameter on my
freshly booted 4.1-rc6.
This produced this nice Warning, then an OOPS:
[ 661.382335] ------------[ cut here ]------------
[ 661.382344] WARNING: CPU: 1 PID: 2903 at ../mm/backing-dev.c:372
bdi_unregister+0x32/0x40()
[ 661.382346] Modules linked in: ctr ccm fuse xt_CHECKSUM iptable_mangle
ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat
nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT xt_tcpudp
tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables
iptable_filter ip_tables x_tables af_packet bnep bluetooth dm_crypt ecb
algif_skcipher af_alg xfs libcrc32c iTCO_wdt iTCO_vendor_support
snd_hda_codec_conexant snd_hda_codec_generic snd_hda_intel snd_hda_controller
snd_hda_codec snd_hda_core snd_hwdep snd_pcm_oss snd_pcm dm_mod coretemp
kvm_intel arc4 kvm snd_seq iwldvm cdc_ether cdc_acm cdc_wdm usbnet mac80211 mii
thinkpad_acpi snd_seq_device snd_timer iwlwifi i2c_i801 snd_mixer_oss pcspkr
serio_raw cfg80211 lpc_ich snd mfd_core shpchp mei_me mei soundcore rfkill
[ 661.382393] tpm_tis battery ac tpm wmi acpi_cpufreq i915 i2c_algo_bit
drm_kms_helper xhci_pci xhci_hcd drm e1000e ptp pps_core video button fan
thermal processor sg loop(-)
[ 661.382408] CPU: 1 PID: 2903 Comm: rmmod Not tainted
4.1.0-rc6-2.g8f2a4d1-desktop #1
[ 661.382410] Hardware name: LENOVO 74665EG/74665EG, BIOS 6DET71WW (3.21 )
12/13/2011
[ 661.382412] 0000000000000000 ffffffff81a4c793 ffffffff8169b34a
0000000000000000
[ 661.382415] ffffffff81067b71 ffff8802307b5400 0000000000000000
0000000000000000
[ 661.382418] 00000000ffffffff 0000000000000000 ffffffff8118cdd2
000000000000000e
[ 661.382421] Call Trace:
[ 661.382434] [<ffffffff810055bc>] dump_trace+0x8c/0x340
[ 661.382438] [<ffffffff8100596c>] show_stack_log_lvl+0xfc/0x1a0
[ 661.382442] [<ffffffff81007071>] show_stack+0x21/0x50
[ 661.382447] [<ffffffff8169b34a>] dump_stack+0x47/0x67
[ 661.382452] [<ffffffff81067b71>] warn_slowpath_common+0x81/0xb0
[ 661.382457] [<ffffffff8118cdd2>] bdi_unregister+0x32/0x40
[ 661.382461] [<ffffffff8133e040>] del_gendisk+0x110/0x280
[ 661.382470] [<ffffffffa0000351>] loop_remove+0x21/0x50 [loop]
[ 661.382476] [<ffffffffa0000391>] loop_exit_cb+0x11/0x20 [loop]
[ 661.382480] [<ffffffff81359743>] idr_for_each+0xa3/0xf0
[ 661.382487] [<ffffffffa0003516>] loop_exit+0x30/0xb1a [loop]
[ 661.382492] [<ffffffff810ece3c>] SyS_delete_module+0x1ac/0x230
[ 661.382497] [<ffffffff816a1cb2>] system_call_fastpath+0x16/0x75
[ 661.382502] [<00007ff635777f37>] 0x7ff635777f37
[ 661.382504] ---[ end trace 7b8e0f39c45cf571 ]---
[ 661.449507] BUG: unable to handle kernel NULL pointer dereference at
0000000000000108
[ 661.449548] IP: [<ffffffff8135b3ce>] kobject_del+0xe/0x50
[ 661.449586] PGD 1d8f2c067 PUD 1d8e7c067 PMD 0
[ 661.449618] Oops: 0000 [#1] PREEMPT SMP
[ 661.449649] Modules linked in: ctr ccm fuse xt_CHECKSUM iptable_mangle
ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat
nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT xt_tcpudp
tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables
iptable_filter ip_tables x_tables af_packet bnep bluetooth dm_crypt ecb
algif_skcipher af_alg xfs libcrc32c iTCO_wdt iTCO_vendor_support
snd_hda_codec_conexant snd_hda_codec_generic snd_hda_intel snd_hda_controller
snd_hda_codec snd_hda_core snd_hwdep snd_pcm_oss snd_pcm dm_mod coretemp
kvm_intel arc4 kvm snd_seq iwldvm cdc_ether cdc_acm cdc_wdm usbnet mac80211 mii
thinkpad_acpi snd_seq_device snd_timer iwlwifi i2c_i801 snd_mixer_oss pcspkr
serio_raw cfg80211 lpc_ich snd mfd_core shpchp mei_me mei soundcore rfkill
[ 661.449906] tpm_tis battery ac tpm wmi acpi_cpufreq i915 i2c_algo_bit
drm_kms_helper xhci_pci xhci_hcd drm e1000e ptp pps_core video button fan
thermal processor sg loop(-)
[ 661.449993] CPU: 0 PID: 2903 Comm: rmmod Tainted: G W
4.1.0-rc6-2.g8f2a4d1-desktop #1
[ 661.450025] Hardware name: LENOVO 74665EG/74665EG, BIOS 6DET71WW (3.21 )
12/13/2011
[ 661.450055] task: ffff8802322220d0 ti: ffff8801d8d78000 task.ti:
ffff8801d8d78000
[ 661.450084] RIP: 0010:[<ffffffff8135b3ce>] [<ffffffff8135b3ce>]
kobject_del+0xe/0x50
[ 661.450118] RSP: 0018:ffff8801d8d7bd78 EFLAGS: 00010206
[ 661.450146] RAX: ffff88023004ab60 RBX: 00000000000000d8 RCX: 0000000000000001
[ 661.450175] RDX: 0000000000000000 RSI: ffff88023078c4d8 RDI: 00000000000000d8
[ 661.450203] RBP: ffff88023004f800 R08: ffff88023215a8b8 R09: ffff88023215b0c8
[ 661.450217] R10: 0001526900015261 R11: 000000000000000e R12: 0000000000000000
[ 661.450217] R13: ffff8802300577e0 R14: ffff88023004f400 R15: ffffffffa0000380
[ 661.450217] FS: 00007ff636056700(0000) GS:ffff88023bc00000(0000)
knlGS:0000000000000000
[ 661.450217] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 661.450217] CR2: 0000000000000108 CR3: 000000023223f000 CR4: 00000000000407f0
[ 661.450217] Stack:
[ 661.450217] ffffffffa0000380 0000000000000001 ffff88023004f800
ffffffff8133abed
[ 661.450217] ffff8802319eba80 ffff8802300577e0 ffff88023004f800
ffffffff8133ac61
[ 661.450217] ffff8802300577e0 ffff88023004f400 0000000000000000
00000000ffffffff
[ 661.450217] Call Trace:
[ 661.450217] [<ffffffff8133abed>] blk_mq_unregister_hctx.part.0+0x3d/0x60
[ 661.450217] [<ffffffff8133ac61>] blk_mq_unregister_disk+0x51/0xe0
[ 661.450217] [<ffffffff81330a2c>] blk_unregister_queue+0x2c/0x90
[ 661.450217] [<ffffffff8133e048>] del_gendisk+0x118/0x280
[ 661.450217] [<ffffffffa0000351>] loop_remove+0x21/0x50 [loop]
[ 661.450217] [<ffffffffa0000391>] loop_exit_cb+0x11/0x20 [loop]
[ 661.450217] [<ffffffff81359743>] idr_for_each+0xa3/0xf0
[ 661.450217] [<ffffffffa0003516>] loop_exit+0x30/0xb1a [loop]
[ 661.450217] [<ffffffff810ece3c>] SyS_delete_module+0x1ac/0x230
[ 661.450217] [<ffffffff816a1cb2>] system_call_fastpath+0x16/0x75
[ 661.450217] [<00007ff635777f37>] 0x7ff635777f37
[ 661.450217] Code: 48 83 c7 18 e9 54 ff ff ff 0f 1f 40 00 5b c3 66 66 66 66
66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 fb 48 83 ec 08 48 85 ff 74 2e <48> 8b
6f 30 e8 09 cc ef ff 48 89 ef e8 a1 98 ef ff 80 63 3c fd
[ 661.450217] RIP [<ffffffff8135b3ce>] kobject_del+0xe/0x50
[ 661.450217] RSP <ffff8801d8d7bd78>
[ 661.450217] CR2: 0000000000000108
[ 661.466690] ---[ end trace 7b8e0f39c45cf572 ]---
I can reproduce the backtrace after a reboot once (subsequent modprobe/rmmod
loop
do not complain anymore), but not the OOPS.
Best regards,
Stefan
--
Stefan Seyfried
Linux Consultant & Developer -- GPG Key: 0x731B665B
B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de
GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt,HRB 3537
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