Re: EFI pstore: BUG: scheduling while atomic, and possible circular locking dependency

[Lingzhu Xiang <lxiang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 11/22/2012 10:57 AM, Lingzhu Xiang wrote:
> mount pstore and crash
> ======================
> 
> [   83.504275] SysRq : Trigger a crash
> [   83.505022] BUG: unable to handle kernel NULL pointer dereference at           (null)
> [   83.505022] IP: [<ffffffff81415d86>] sysrq_handle_crash+0x16/0x20
> [   83.505022] PGD 9ea4067 PUD 9e1a067 PMD 0
> [   83.505022] Oops: 0002 [#1] SMP
> [   83.505022] Modules linked in: ipt_MASQUERADE nf_conntrack_netbios_ns nf_conntrack_broadcast ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack vfat fat microcode virtio_net i2c_piix4 i2c_core
> [   83.505022] CPU 2
> [   83.505022] Pid: 797, comm: bash Tainted: G        W    3.7.0-0.rc5.git2.1.fc19.x86_64 #1
> [   83.505022] RIP: 0010:[<ffffffff81415d86>]  [<ffffffff81415d86>] sysrq_handle_crash+0x16/0x20
> [   83.505022] RSP: 0018:ffff88001a7abe28  EFLAGS: 00010096
> [   83.505022] RAX: 000000000000000f RBX: ffffffff81cc28a0 RCX: 0000000000000000
> [   83.505022] RDX: ffff880005182690 RSI: 0000000000000000 RDI: 0000000000000063
> [   83.505022] RBP: ffff88001a7abe28 R08: 0000000000000001 R09: 0000000000000001
> [   83.505022] R10: 0000000000000002 R11: 000000000000029c R12: 0000000000000063
> [   83.505022] R13: 0000000000000282 R14: 0000000000000000 R15: 000000000000000a
> [   83.505022] FS:  00007fa8d353a740(0000) GS:ffff88001b000000(0000) knlGS:0000000000000000
> [   83.505022] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   83.505022] CR2: 0000000000000000 CR3: 0000000007fd3000 CR4: 00000000000406e0
> [   83.505022] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [   83.505022] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [   83.505022] Process bash (pid: 797, threadinfo ffff88001a7aa000, task ffff880005182690)
> [   83.505022] Stack:
> [   83.505022]  ffff88001a7abe68 ffffffff81416547 ffff88001a7abe68 0000000000000002
> [   83.505022]  ffff8800188aa940 ffffffff814165b0 ffff880016cde2b8 ffff88001a7abf50
> [   83.505022]  ffff88001a7abe98 ffffffff814165fa ffff88001a7abe98 00007fa8d3541000
> [   83.505022] Call Trace:
> [   83.505022]  [<ffffffff81416547>] __handle_sysrq+0x127/0x190
> [   83.505022]  [<ffffffff814165b0>] ? __handle_sysrq+0x190/0x190
> [   83.505022]  [<ffffffff814165fa>] write_sysrq_trigger+0x4a/0x50
> [   83.505022]  [<ffffffff81242770>] proc_reg_write+0x80/0xc0
> [   83.505022]  [<ffffffff811d2eff>] vfs_write+0xaf/0x190
> [   83.505022]  [<ffffffff811d3255>] sys_write+0x55/0xa0
> [   83.505022]  [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> [   83.505022] Code: c1 f7 ff ff eb d8 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 66 66 66 66 90 55 c7 05 cc f4 cb 00 01 00 00 00 48 89 e5 0f ae f8 <c6> 04 25 00 00 00 00 01 5d c3 66 66 66 66 90 55 31 c0 48 89 e5
> [   83.505022] RIP  [<ffffffff81415d86>] sysrq_handle_crash+0x16/0x20
> [   83.505022]  RSP <ffff88001a7abe28>
> [   83.505022] CR2: 0000000000000000
> [   83.505022] ---[ end trace b0c0c16a378b5fe5 ]---
> [   83.505022] BUG: sleeping function called from invalid context at mm/slub.c:928
> [   83.505022] in_atomic(): 1, irqs_disabled(): 1, pid: 797, name: bash
> [   83.505022] INFO: lockdep is turned off.
> [   83.505022] irq event stamp: 54760
> [   83.505022] hardirqs last  enabled at (54759): [<ffffffff816f2858>] retint_swapgs+0x13/0x1b
> [   83.505022] hardirqs last disabled at (54760): [<ffffffff816f2392>] _raw_spin_lock_irqsave+0x32/0xb0
> [   83.505022] softirqs last  enabled at (54672): [<ffffffff81072977>] __do_softirq+0x167/0x3d0
> [   83.505022] softirqs last disabled at (54655): [<ffffffff816fcb7c>] call_softirq+0x1c/0x30
> [   83.505022] Pid: 797, comm: bash Tainted: G      D W    3.7.0-0.rc5.git2.1.fc19.x86_64 #1
> [   83.505022] Call Trace:
> [   83.505022]  [<ffffffff810d59a0>] ? print_irqtrace_events+0xd0/0xe0
> [   83.505022]  [<ffffffff810a401d>] __might_sleep+0x18d/0x250
> [   83.505022]  [<ffffffff811b9dc7>] __kmalloc+0x67/0x2d0
> [   83.505022]  [<ffffffff8156375b>] ? efivar_create_sysfs_entry+0x3b/0x1b0
> [   83.505022]  [<ffffffff8156375b>] efivar_create_sysfs_entry+0x3b/0x1b0
> [   83.505022]  [<ffffffff81563c03>] efi_pstore_write+0x333/0x3a0
> [   83.505022]  [<ffffffff8106a3fe>] ? kmsg_dump_get_buffer+0x24e/0x2b0
> [   83.505022]  [<ffffffff812ca4c5>] ? pstore_dump+0x195/0x210
> [   83.505022]  [<ffffffff812ca45f>] pstore_dump+0x12f/0x210
> [   83.505022]  [<ffffffff8106c459>] kmsg_dump+0xf9/0x240
> [   83.505022]  [<ffffffff8106c385>] ? kmsg_dump+0x25/0x240
> [   83.505022]  [<ffffffff81068a49>] oops_exit+0x29/0x30
> [   83.505022]  [<ffffffff816f37c3>] oops_end+0x73/0xe0
> [   83.505022]  [<ffffffff816e48bf>] no_context+0x258/0x283
> [   83.505022]  [<ffffffff816e4ab4>] __bad_area_nosemaphore+0x1ca/0x1e9
> [   83.505022]  [<ffffffff816e4ae6>] bad_area_nosemaphore+0x13/0x15
> [   83.505022]  [<ffffffff816f67ce>] __do_page_fault+0x2ae/0x580
> [   83.505022]  [<ffffffff810d258d>] ? trace_hardirqs_off+0xd/0x10
> [   83.505022]  [<ffffffff816f2257>] ? _raw_spin_unlock_irqrestore+0x77/0x80
> [   83.505022]  [<ffffffff8106a97d>] ? console_unlock+0x1ed/0x4a0
> [   83.505022]  [<ffffffff816f6aae>] do_page_fault+0xe/0x10
> [   83.505022]  [<ffffffff816f6195>] do_async_page_fault+0x35/0xa0
> [   83.505022]  [<ffffffff816f2b78>] async_page_fault+0x28/0x30
> [   83.505022]  [<ffffffff81415d86>] ? sysrq_handle_crash+0x16/0x20
> [   83.505022]  [<ffffffff81416547>] __handle_sysrq+0x127/0x190
> [   83.505022]  [<ffffffff814165b0>] ? __handle_sysrq+0x190/0x190
> [   83.505022]  [<ffffffff814165fa>] write_sysrq_trigger+0x4a/0x50
> [   83.505022]  [<ffffffff81242770>] proc_reg_write+0x80/0xc0
> [   83.505022]  [<ffffffff811d2eff>] vfs_write+0xaf/0x190
> [   83.505022]  [<ffffffff811d3255>] sys_write+0x55/0xa0
> [   83.505022]  [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> [   83.596022] BUG: scheduling while atomic: bash/797/0x10000004
> [   83.596744] INFO: lockdep is turned off.
> [   83.603006] Modules linked in: ipt_MASQUERADE nf_conntrack_netbios_ns nf_conntrack_broadcast ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack vfat fat microcode virtio_net i2c_piix4 i2c_core
> [   83.609408] Pid: 797, comm: bash Tainted: G      D W    3.7.0-0.rc5.git2.1.fc19.x86_64 #1
> [   83.620001] Call Trace:
> [   83.620461]  [<ffffffff816e570c>] __schedule_bug+0x68/0x76
> [   83.621888]  [<ffffffff816f030e>] __schedule+0x99e/0xa00
> [   83.623166]  [<ffffffff810a68ca>] __cond_resched+0x2a/0x40
> [   83.624160]  [<ffffffff816f03ef>] _cond_resched+0x2f/0x40
> [   83.625516]  [<ffffffff8116b510>] __alloc_pages_nodemask+0x2d0/0xb40
> [   83.626721]  [<ffffffff816f228b>] ? _raw_spin_unlock+0x2b/0x50
> [   83.627783]  [<ffffffff811b7fb7>] ? deactivate_slab+0x567/0x7d0
> [   83.629012]  [<ffffffff8111efb7>] ? rcu_irq_exit+0x87/0xd0
> [   83.629958]  [<ffffffff811ad3a0>] alloc_pages_current+0xb0/0x120
> [   83.631013]  [<ffffffff811b7925>] ? new_slab+0x275/0x3a0
> [   83.631878]  [<ffffffff811b7970>] new_slab+0x2c0/0x3a0
> [   83.632752]  [<ffffffff816e8848>] __slab_alloc+0x3a2/0x58f
> [   83.633697]  [<ffffffff8125492e>] ? sysfs_new_dirent+0x2e/0x130
> [   83.634710]  [<ffffffff81254959>] ? sysfs_new_dirent+0x59/0x130
> [   83.635719]  [<ffffffff810d1d64>] ? mutex_remove_waiter+0x44/0x120
> [   83.636767]  [<ffffffff81254959>] ? sysfs_new_dirent+0x59/0x130
> [   83.637767]  [<ffffffff811b9087>] kmem_cache_alloc+0x237/0x290
> [   83.643006]  [<ffffffff81254959>] sysfs_new_dirent+0x59/0x130
> [   83.644065]  [<ffffffff81254d0b>] ? sysfs_addrm_finish+0x1b/0x70
> [   83.645256]  [<ffffffff81253b3b>] sysfs_add_file_mode+0x6b/0x110
> [   83.646410]  [<ffffffff81253bf2>] sysfs_add_file+0x12/0x20
> [   83.647485]  [<ffffffff81253cc6>] sysfs_create_file+0x26/0x30
> [   83.653019]  [<ffffffff8134f13c>] kobject_add_internal+0x15c/0x270
> [   83.654105]  [<ffffffff8134f643>] kobject_init_and_add+0x63/0x90
> [   83.655228]  [<ffffffff81563844>] efivar_create_sysfs_entry+0x124/0x1b0
> [   83.656753]  [<ffffffff81563c03>] efi_pstore_write+0x333/0x3a0
> [   83.657932]  [<ffffffff8106a3fe>] ? kmsg_dump_get_buffer+0x24e/0x2b0
> [   83.663008]  [<ffffffff812ca4c5>] ? pstore_dump+0x195/0x210
> [   83.664032]  [<ffffffff812ca45f>] pstore_dump+0x12f/0x210
> [   83.664993]  [<ffffffff8106c459>] kmsg_dump+0xf9/0x240
> [   83.666077]  [<ffffffff8106c385>] ? kmsg_dump+0x25/0x240
> [   83.667124]  [<ffffffff81068a49>] oops_exit+0x29/0x30
> [   83.668147]  [<ffffffff816f37c3>] oops_end+0x73/0xe0
> [   83.673005]  [<ffffffff816e48bf>] no_context+0x258/0x283
> [   83.674916]  [<ffffffff816e4ab4>] __bad_area_nosemaphore+0x1ca/0x1e9
> [   83.677798]  [<ffffffff816e4ae6>] bad_area_nosemaphore+0x13/0x15
> [   83.680031]  [<ffffffff816f67ce>] __do_page_fault+0x2ae/0x580
> [   83.681694]  [<ffffffff810d258d>] ? trace_hardirqs_off+0xd/0x10
> [   83.691002]  [<ffffffff816f2257>] ? _raw_spin_unlock_irqrestore+0x77/0x80
> [   83.692209]  [<ffffffff8106a97d>] ? console_unlock+0x1ed/0x4a0
> [   83.693481]  [<ffffffff816f6aae>] do_page_fault+0xe/0x10
> [   83.694577]  [<ffffffff816f6195>] do_async_page_fault+0x35/0xa0
> [   83.695696]  [<ffffffff816f2b78>] async_page_fault+0x28/0x30
> [   83.696676]  [<ffffffff81415d86>] ? sysrq_handle_crash+0x16/0x20
> [   83.697674]  [<ffffffff81416547>] __handle_sysrq+0x127/0x190
> [   83.699098]  [<ffffffff814165b0>] ? __handle_sysrq+0x190/0x190
> [   83.700142]  [<ffffffff814165fa>] write_sysrq_trigger+0x4a/0x50
> [   83.701284]  [<ffffffff81242770>] proc_reg_write+0x80/0xc0
> [   83.710005]  [<ffffffff811d2eff>] vfs_write+0xaf/0x190
> [   83.710998]  [<ffffffff811d3255>] sys_write+0x55/0xa0
> [   83.711900]  [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> 
> After reboot, mount pstore
> ==========================
> 
> [root@localhost ~]# mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
> [   36.502832] BUG: sleeping function called from invalid context at mm/slub.c:928
> [   36.504379] in_atomic(): 1, irqs_disabled(): 0, pid: 851, name: mount
> [   36.505652] 3 locks held by mount/851:
> [   36.506355]  #0:  (&type->s_umount_key#38/1){+.+.+.}, at: [<ffffffff811d5aed>] sget+0x37d/0x640
> [   36.508899]  #1:  (&psinfo->read_mutex){+.+.+.}, at: [<ffffffff812ca59b>] pstore_get_records+0x3b/0x130
> [   36.510688]  #2:  (&(&efivars->lock)->rlock){+.+.+.}, at: [<ffffffff8156273d>] efi_pstore_open+0x1d/0x40
> [   36.512468] Pid: 851, comm: mount Tainted: G        W    3.7.0-0.rc5.git2.1.fc19.x86_64 #1
> [   36.514001] Call Trace:
> [   36.514440]  [<ffffffff810a401d>] __might_sleep+0x18d/0x250
> [   36.515634]  [<ffffffff811b9dc7>] __kmalloc+0x67/0x2d0
> [   36.516509]  [<ffffffff81562103>] ? efi_pstore_read+0x1c3/0x220
> [   36.517525]  [<ffffffff81562103>] efi_pstore_read+0x1c3/0x220
> [   36.518507]  [<ffffffff812ca5f1>] pstore_get_records+0x91/0x130
> [   36.519524]  [<ffffffff812eddfc>] ? selinux_d_instantiate+0x1c/0x20
> [   36.520586]  [<ffffffff812c9c10>] ? pstore_get_inode+0x50/0x50
> [   36.521566]  [<ffffffff812c9cb2>] pstore_fill_super+0xa2/0xc0
> [   36.522542]  [<ffffffff811d6b42>] mount_single+0xb2/0xe0
> [   36.523449]  [<ffffffff812c9a98>] pstore_mount+0x18/0x20
> [   36.524322]  [<ffffffff811d6d63>] mount_fs+0x43/0x1b0
> [   36.525360]  [<ffffffff811f4ee3>] vfs_kern_mount+0x73/0x110
> [   36.526408]  [<ffffffff811f5984>] do_kern_mount+0x54/0x110
> [   36.530014]  [<ffffffff811f7535>] do_mount+0x315/0x8e0
> [   36.531181]  [<ffffffff811f708a>] ? copy_mount_options+0x3a/0x180
> [   36.532390]  [<ffffffff811f7b8e>] sys_mount+0x8e/0xe0
> [   36.533438]  [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> [   36.540017] BUG: scheduling while atomic: mount/851/0x10000002
> [   36.541315] 3 locks held by mount/851:
> [   36.541952]  #0:  (&type->s_umount_key#38/1){+.+.+.}, at: [<ffffffff811d5aed>] sget+0x37d/0x640
> [   36.544260]  #1:  (&psinfo->read_mutex){+.+.+.}, at: [<ffffffff812ca59b>] pstore_get_records+0x3b/0x130
> [   36.546146]  #2:  (&(&efivars->lock)->rlock){+.+.+.}, at: [<ffffffff8156273d>] efi_pstore_open+0x1d/0x40
> [   36.547964] Modules linked in: ipt_MASQUERADE nf_conntrack_netbios_ns nf_conntrack_broadcast ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack vfat fat microcode i2c_piix4 i2c_core virtio_net
> [   36.560478] Pid: 851, comm: mount Tainted: G        W    3.7.0-0.rc5.git2.1.fc19.x86_64 #1
> [   36.562019] Call Trace:
> [   36.562655]  [<ffffffff816e570c>] __schedule_bug+0x68/0x76
> [   36.570017]  [<ffffffff816f030e>] __schedule+0x99e/0xa00
> [   36.570915]  [<ffffffff810a68ca>] __cond_resched+0x2a/0x40
> [   36.571974]  [<ffffffff816f03ef>] _cond_resched+0x2f/0x40
> [   36.573279]  [<ffffffff811b9dcc>] __kmalloc+0x6c/0x2d0
> [   36.574642]  [<ffffffff81562103>] ? efi_pstore_read+0x1c3/0x220
> [   36.576426]  [<ffffffff81562103>] efi_pstore_read+0x1c3/0x220
> [   36.577679]  [<ffffffff812ca5f1>] pstore_get_records+0x91/0x130
> [   36.578981]  [<ffffffff812eddfc>] ? selinux_d_instantiate+0x1c/0x20
> [   36.585520]  [<ffffffff812c9c10>] ? pstore_get_inode+0x50/0x50
> [   36.586595]  [<ffffffff812c9cb2>] pstore_fill_super+0xa2/0xc0
> [   36.587648]  [<ffffffff811d6b42>] mount_single+0xb2/0xe0
> [   36.588625]  [<ffffffff812c9a98>] pstore_mount+0x18/0x20
> [   36.590078]  [<ffffffff811d6d63>] mount_fs+0x43/0x1b0
> [   36.591511]  [<ffffffff811f4ee3>] vfs_kern_mount+0x73/0x110
> [   36.592847]  [<ffffffff811f5984>] do_kern_mount+0x54/0x110
> [   36.600017]  [<ffffffff811f7535>] do_mount+0x315/0x8e0
> [   36.601128]  [<ffffffff811f708a>] ? copy_mount_options+0x3a/0x180
> [   36.602257]  [<ffffffff811f7b8e>] sys_mount+0x8e/0xe0
> [   36.603221]  [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> 
> After reboot, rm a pstore entry
> ===============================
> 
> [root@localhost ~]# rm -f /dev/pstore/dmesg-efi-9
> [   55.572466]
> [   55.572767] ======================================================
> [   55.573015] [ INFO: possible circular locking dependency detected ]
> [   55.573015] 3.7.0-0.rc5.git2.1.fc19.x86_64 #1 Tainted: G        W
> [   55.573015] -------------------------------------------------------
> [   55.573015] rm/855 is trying to acquire lock:
> [   55.573015]  (&(&efivars->lock)->rlock){+.+.+.}, at: [<ffffffff815639c5>] efi_pstore_write+0xf5/0x3a0
> [   55.573015]
> [   55.573015] but task is already holding lock:
> [   55.573015]  (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffff811e0a53>] vfs_unlink+0x53/0x110
> [   55.573015]
> [   55.573015] which lock already depends on the new lock.
> [   55.573015]
> [   55.573015]
> [   55.573015] the existing dependency chain (in reverse order) is:
> [   55.573015]
> -> #1 (&sb->s_type->i_mutex_key#15){+.+.+.}:
> [   55.573015]        [<ffffffff810d7ee1>] lock_acquire+0xa1/0x1f0
> [   55.573015]        [<ffffffff816ee226>] mutex_lock_nested+0x76/0x390
> [   55.573015]        [<ffffffff812ca0dc>] pstore_mkfile+0x1bc/0x390
> [   55.573015]        [<ffffffff812ca621>] pstore_get_records+0xc1/0x130
> [   55.573015]        [<ffffffff812c9cb2>] pstore_fill_super+0xa2/0xc0
> [   55.573015]        [<ffffffff811d6b42>] mount_single+0xb2/0xe0
> [   55.573015]        [<ffffffff812c9a98>] pstore_mount+0x18/0x20
> [   55.573015]        [<ffffffff811d6d63>] mount_fs+0x43/0x1b0
> [   55.573015]        [<ffffffff811f4ee3>] vfs_kern_mount+0x73/0x110
> [   55.573015]        [<ffffffff811f5984>] do_kern_mount+0x54/0x110
> [   55.573015]        [<ffffffff811f7535>] do_mount+0x315/0x8e0
> [   55.573015]        [<ffffffff811f7b8e>] sys_mount+0x8e/0xe0
> [   55.573015]        [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> [   55.573015]
> -> #0 (&(&efivars->lock)->rlock){+.+.+.}:
> [   55.573015]        [<ffffffff810d775f>] __lock_acquire+0x1aff/0x1bb0
> [   55.573015]        [<ffffffff810d7ee1>] lock_acquire+0xa1/0x1f0
> [   55.573015]        [<ffffffff816f17a6>] _raw_spin_lock+0x46/0x80
> [   55.573015]        [<ffffffff815639c5>] efi_pstore_write+0xf5/0x3a0
> [   55.573015]        [<ffffffff81563c95>] efi_pstore_erase+0x25/0x30
> [   55.573015]        [<ffffffff812c9adf>] pstore_unlink+0x3f/0x60
> [   55.573015]        [<ffffffff811e0a9e>] vfs_unlink+0x9e/0x110
> [   55.573015]        [<ffffffff811e0c11>] do_unlinkat+0x101/0x1b0
> [   55.573015]        [<ffffffff811e368b>] sys_unlinkat+0x1b/0x40
> [   55.573015]        [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b
> [   55.573015]
> [   55.573015] other info that might help us debug this:
> [   55.573015]
> [   55.573015]  Possible unsafe locking scenario:
> [   55.573015]
> [   55.573015]        CPU0                    CPU1
> [   55.573015]        ----                    ----
> [   55.573015]   lock(&sb->s_type->i_mutex_key#15);
> [   55.573015]                                lock(&(&efivars->lock)->rlock);
> [   55.573015]                                lock(&sb->s_type->i_mutex_key#15);
> [   55.573015]   lock(&(&efivars->lock)->rlock);
> [   55.573015]
> [   55.573015]  *** DEADLOCK ***
> [   55.573015]
> [   55.573015] 3 locks held by rm/855:
> [   55.573015]  #0:  (sb_writers#12){.+.+..}, at: [<ffffffff811f5c24>] mnt_want_write+0x24/0x50
> [   55.573015]  #1:  (&sb->s_type->i_mutex_key#15/1){+.+...}, at: [<ffffffff811e0bbb>] do_unlinkat+0xab/0x1b0
> [   55.573015]  #2:  (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffff811e0a53>] vfs_unlink+0x53/0x110
> [   55.573015]
> [   55.573015] stack backtrace:
> [   55.573015] Pid: 855, comm: rm Tainted: G        W    3.7.0-0.rc5.git2.1.fc19.x86_64 #1
> [   55.573015] Call Trace:
> [   55.573015]  [<ffffffff816e608f>] print_circular_bug+0x1fb/0x20c
> [   55.573015]  [<ffffffff810d775f>] __lock_acquire+0x1aff/0x1bb0
> [   55.573015]  [<ffffffff81356bdb>] ? number.isra.2+0x35b/0x390
> [   55.573015]  [<ffffffff810d7ee1>] lock_acquire+0xa1/0x1f0
> [   55.573015]  [<ffffffff815639c5>] ? efi_pstore_write+0xf5/0x3a0
> [   55.573015]  [<ffffffff816f17a6>] _raw_spin_lock+0x46/0x80
> [   55.573015]  [<ffffffff815639c5>] ? efi_pstore_write+0xf5/0x3a0
> [   55.573015]  [<ffffffff815639c5>] efi_pstore_write+0xf5/0x3a0
> [   55.573015]  [<ffffffff810d258d>] ? trace_hardirqs_off+0xd/0x10
> [   55.573015]  [<ffffffff810ace0f>] ? local_clock+0x6f/0x80
> [   55.573015]  [<ffffffff810d2f0f>] ? lock_release_holdtime.part.26+0xf/0x180
> [   55.573015]  [<ffffffff812e5ccb>] ? avc_has_perm_flags+0x17b/0x2c0
> [   55.573015]  [<ffffffff812e5b79>] ? avc_has_perm_flags+0x29/0x2c0
> [   55.573015]  [<ffffffff81563c95>] efi_pstore_erase+0x25/0x30
> [   55.573015]  [<ffffffff812c9adf>] pstore_unlink+0x3f/0x60
> [   55.573015]  [<ffffffff811e0a9e>] vfs_unlink+0x9e/0x110
> [   55.573015]  [<ffffffff811e0c11>] do_unlinkat+0x101/0x1b0
> [   55.573015]  [<ffffffff810d8a6d>] ? trace_hardirqs_on_caller+0x10d/0x1a0
> [   55.573015]  [<ffffffff8110495c>] ? __audit_syscall_entry+0xcc/0x300
> [   55.573015]  [<ffffffff8135a76e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> [   55.573015]  [<ffffffff811e368b>] sys_unlinkat+0x1b/0x40
> [   55.573015]  [<ffffffff816fb8d9>] system_call_fastpath+0x16/0x1b

I was just verifying this bug with Fedora 3.9-rc6 kernel containing
81fa4e581d9283f7992a0d8c534bb141eb840a14 efivars: Disable external interrupt while holding efivars->lock
a93bc0c6e07ed9bac44700280e65e2945d864fd4 efi_pstore: Introducing workqueue updating sysfs

Booted kernel with pstore.backend=efi efivars.pstore_disable=N.

Apparently there is no longer any efi pstore call trace during panic.

After reboot, mounting pstore still produces similar call traces:

[root@ibm-x3550m3-02 ~]# mount -t pstore - /sys/fs/pstore/
[   90.896585] ------------[ cut here ]------------
[   90.901213] WARNING: at kernel/lockdep.c:2739 lockdep_trace_alloc+0xd5/0xe0()
[   90.908350] Hardware name: System x3550 M3 -[7944I21]-
[   90.913487] Modules linked in: vfat fat iTCO_wdt iTCO_vendor_support cdc_ether usbnet lpc_ich shpchp serio_raw bnx2 acpi_cpufreq mperf coretemp mii kvm_intel kvm crc32c_intel i2c_i801 i7core_edac microcode ioatdma mfd_core edac_core dca mgag200 i2c_algo_bit drm_kms_helper mptsas ttm mptscsih drm mptbase i2c_core scsi_transport_sas
[   90.943439] Pid: 945, comm: mount Tainted: G        W    3.9.0-0.rc6.git2.1.fc19.x86_64 #1
[   90.951702] Call Trace:
[   90.954157]  [<ffffffff81068e26>] warn_slowpath_common+0x66/0x80
[   90.960168]  [<ffffffff81589825>] ? efi_pstore_read+0x225/0x2d0
[   90.966090]  [<ffffffff81068efa>] warn_slowpath_null+0x1a/0x20
[   90.971925]  [<ffffffff810db7b5>] lockdep_trace_alloc+0xd5/0xe0
[   90.977848]  [<ffffffff811bcc9f>] __kmalloc+0x4f/0x390
[   90.982991]  [<ffffffff81589825>] efi_pstore_read+0x225/0x2d0
[   90.988743]  [<ffffffff815876a9>] ? efi_pstore_open+0x19/0x30
[   90.994492]  [<ffffffff812d543a>] pstore_get_records+0x9a/0x150
[   91.000414]  [<ffffffff812f8b8c>] ? selinux_d_instantiate+0x1c/0x20
[   91.006682]  [<ffffffff812d4b20>] ? parse_options+0x80/0x80
[   91.012256]  [<ffffffff812d4bc5>] pstore_fill_super+0xa5/0xc0
[   91.018005]  [<ffffffff811debb2>] mount_single+0xa2/0xd0
[   91.023321]  [<ffffffff812d49e8>] pstore_mount+0x18/0x20
[   91.028636]  [<ffffffff811deca9>] mount_fs+0x39/0x1b0
[   91.033693]  [<ffffffff811fc943>] vfs_kern_mount+0x63/0xf0
[   91.039183]  [<ffffffff811ff04d>] do_mount+0x1fd/0xa00
[   91.044323]  [<ffffffff811fecd6>] ? copy_mount_options+0x36/0x170
[   91.050420]  [<ffffffff811ff8d3>] sys_mount+0x83/0xc0
[   91.055475]  [<ffffffff81723019>] system_call_fastpath+0x16/0x1b
[   91.061480] ---[ end trace dfa024323430202e ]---
[   91.066101] BUG: sleeping function called from invalid context at mm/slub.c:925
[   91.073408] in_atomic(): 1, irqs_disabled(): 1, pid: 945, name: mount
[   91.079847] INFO: lockdep is turned off.
[   91.083773] irq event stamp: 5910
[   91.087089] hardirqs last  enabled at (5909): [<ffffffff81716063>] mutex_lock_nested+0x313/0x3c0
[   91.095892] hardirqs last disabled at (5910): [<ffffffff8171928f>] _raw_spin_lock_irq+0x1f/0x90
[   91.104613] softirqs last  enabled at (5898): [<ffffffff81073503>] __do_softirq+0x193/0x400
[   91.112987] softirqs last disabled at (5893): [<ffffffff81073935>] irq_exit+0xb5/0xc0
[   91.120839] Pid: 945, comm: mount Tainted: G        W    3.9.0-0.rc6.git2.1.fc19.x86_64 #1
[   91.129103] Call Trace:
[   91.131555]  [<ffffffff810a32b9>] __might_sleep+0x179/0x230
[   91.137130]  [<ffffffff811bccb7>] __kmalloc+0x67/0x390
[   91.142272]  [<ffffffff81589825>] efi_pstore_read+0x225/0x2d0
[   91.148020]  [<ffffffff815876a9>] ? efi_pstore_open+0x19/0x30
[   91.153769]  [<ffffffff812d543a>] pstore_get_records+0x9a/0x150
[   91.159691]  [<ffffffff812f8b8c>] ? selinux_d_instantiate+0x1c/0x20
[   91.165961]  [<ffffffff812d4b20>] ? parse_options+0x80/0x80
[   91.171536]  [<ffffffff812d4bc5>] pstore_fill_super+0xa5/0xc0
[   91.177284]  [<ffffffff811debb2>] mount_single+0xa2/0xd0
[   91.182599]  [<ffffffff812d49e8>] pstore_mount+0x18/0x20
[   91.187916]  [<ffffffff811deca9>] mount_fs+0x39/0x1b0
[   91.192970]  [<ffffffff811fc943>] vfs_kern_mount+0x63/0xf0
[   91.198460]  [<ffffffff811ff04d>] do_mount+0x1fd/0xa00
[   91.203601]  [<ffffffff811fecd6>] ? copy_mount_options+0x36/0x170
[   91.209694]  [<ffffffff811ff8d3>] sys_mount+0x83/0xc0
[   91.214748]  [<ffffffff81723019>] system_call_fastpath+0x16/0x1b
[   91.291775] pstore: failed to load 1 record(s) from 'efi'
[   91.297464] SELinux: initialized (dev pstore, type pstore), not configured for labeling

(Repeat for each entry)

rm -f /sys/fs/pstore/* is fine.

rm -f /sys/firmware/efi/efivars/dump-* && cat /sys/fs/pstore/* is fine.

rm -f /sys/fs/pstore/* && cat /sys/firmware/efi/efivars/dump-* will explode:

[root@ibm-x3550m3-02 ~]# rm -f /sys/fs/pstore/*
[root@ibm-x3550m3-02 ~]# cat /sys/firmware/efi/efivars/dump-* >/dev/null
[  110.082560] general protection fault: 0000 [#1] SMP 
[  110.087570] Modules linked in: vfat(F) fat(F) acpi_cpufreq(F) mperf(F) coretemp(F) kvm_intel(F) kvm(F) crc32c_intel(F) iTCO_wdt(F) cdc_ether(F) iTCO_vendor_support(F) usbnet(F) shpchp(F) i7core_edac(F) ioatdma(F) mii(F) lpc_ich(F) microcode(F) serio_raw(F) edac_core(F) dca(F) i2c_i801(F) mfd_core(F) bnx2(F) mgag200(F) i2c_algo_bit(F) mptsas(F) drm_kms_helper(F) mptscsih(F) ttm(F) mptbase(F) drm(F) scsi_transport_sas(F) i2c_core(F)
[  110.126374] CPU 0 
[  110.128221] Pid: 6182, comm: cat Tainted: GF       W    3.9.0-0.rc6.git2.1.eficheck.fc19.x86_64 #1 IBM System x3550 M3 -[7944I21]-/69Y4438     
[  110.141273] RIP: 0010:[<ffffffff8137ca70>]  [<ffffffff8137ca70>] do_raw_spin_lock+0x150/0x150
[  110.149820] RSP: 0018:ffff88026e45fe60  EFLAGS: 00010046
[  110.155135] RAX: ffff8802710e4dc0 RBX: 6b6b6b6b6b6b6b6b RCX: 0000000000000000
[  110.162270] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 6b6b6b6b6b6b6b6b
[  110.169403] RBP: ffff88026e45fe88 R08: 0000000000000002 R09: 0000000000000001
[  110.176536] R10: ffff8802710e4dc0 R11: 0000000000000246 R12: 6b6b6b6b6b6b6b83
[  110.183669] R13: ffff880470a837e0 R14: ffff88026e45ff50 R15: ffff88026e45ff50
[  110.190804] FS:  00007fcab5c99740(0000) GS:ffff880276600000(0000) knlGS:0000000000000000
[  110.198893] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  110.204640] CR2: 00000000007b5038 CR3: 000000026d773000 CR4: 00000000000007f0
[  110.211773] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  110.218908] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  110.226042] Process cat (pid: 6182, threadinfo ffff88026e45e000, task ffff8802710e4dc0)
[  110.234042] Stack:
[  110.236059]  ffffffff8173407a ffffffff8159f233 ffff88026e5e5290 6b6b6b6b6b6b6b6b
[  110.243533]  ffff880470a833e0 ffff88026e45fef8 ffffffff8159f233 ffff88026e45fec8
[  110.251008]  ffffffff812f99a5 0000000000010000 00000000007a5000 ffff88026e5e5280
[  110.258483] Call Trace:
[  110.260937]  [<ffffffff8173407a>] ? _raw_spin_lock_irq+0x5a/0x90
[  110.266949]  [<ffffffff8159f233>] ? efivarfs_file_read+0x53/0x180
[  110.273045]  [<ffffffff8159f233>] efivarfs_file_read+0x53/0x180
[  110.278968]  [<ffffffff812f99a5>] ? security_file_permission+0x95/0xb0
[  110.285501]  [<ffffffff811e0f4c>] vfs_read+0xac/0x180
[  110.290554]  [<ffffffff811e11d5>] sys_read+0x55/0xa0
[  110.295525]  [<ffffffff8173e159>] system_call_fastpath+0x16/0x1b
[  110.301529] Code: 81 48 89 df e8 f0 00 3b 00 e9 04 ff ff ff 48 c7 c6 9b 0f a4 81 e8 df 00 3b 00 e9 e0 fe ff ff 66 66 66 2e 0f 1f 84 00 00 00 00 00 <8b> 17 55 31 c9 48 89 e5 89 d0 c1 e8 10 66 39 c2 74 0e 89 c8 5d 
[  110.321713] RIP  [<ffffffff8137ca70>] do_raw_spin_lock+0x150/0x150
[  110.327915]  RSP <ffff88026e45fe60>
[  110.331406] ---[ end trace 99f3bec2f519b797 ]---
[  110.611415] BUG: sleeping function called from invalid context at kernel/rwsem.c:20
[  110.619070] in_atomic(): 1, irqs_disabled(): 1, pid: 6182, name: cat
[  110.625425] INFO: lockdep is turned off.
[  110.629351] irq event stamp: 0
[  110.632409] hardirqs last  enabled at (0): [<          (null)>]           (null)
[  110.639823] hardirqs last disabled at (0): [<ffffffff81068218>] copy_process.part.22+0x5e8/0x1650
[  110.648716] softirqs last  enabled at (0): [<ffffffff81068218>] copy_process.part.22+0x5e8/0x1650
[  110.657604] softirqs last disabled at (0): [<          (null)>]           (null)
[  110.665018] Pid: 6182, comm: cat Tainted: GF     D W    3.9.0-0.rc6.git2.1.eficheck.fc19.x86_64 #1
[  110.673976] Call Trace:
[  110.676429]  [<ffffffff810da610>] ? print_irqtrace_events+0xd0/0xe0
[  110.682699]  [<ffffffff810a59fb>] __might_sleep+0x18b/0x250
[  110.688274]  [<ffffffff8173151a>] down_read+0x2a/0x98
[  110.693329]  [<ffffffff81084a34>] exit_signals+0x24/0x130
[  110.698732]  [<ffffffff81070bed>] do_exit+0xbd/0xc90
[  110.703701]  [<ffffffff8106df18>] ? kmsg_dump+0x1b8/0x240
[  110.709101]  [<ffffffff8106dd85>] ? kmsg_dump+0x25/0x240
[  110.714419]  [<ffffffff81735f83>] oops_end+0xa3/0xf0
[  110.719392]  [<ffffffff8101eb18>] die+0x58/0x90
[  110.723925]  [<ffffffff817359b2>] do_general_protection+0xe2/0x170
[  110.730106]  [<ffffffff81735023>] ? restore_args+0x30/0x30
[  110.735596]  [<ffffffff81735298>] general_protection+0x28/0x30
[  110.741430]  [<ffffffff8137ca70>] ? do_raw_spin_lock+0x150/0x150
[  110.747440]  [<ffffffff8173407a>] ? _raw_spin_lock_irq+0x5a/0x90
[  110.753448]  [<ffffffff8159f233>] ? efivarfs_file_read+0x53/0x180
[  110.759542]  [<ffffffff8159f233>] efivarfs_file_read+0x53/0x180
[  110.765466]  [<ffffffff812f99a5>] ? security_file_permission+0x95/0xb0
[  110.771998]  [<ffffffff811e0f4c>] vfs_read+0xac/0x180
[  110.777052]  [<ffffffff811e11d5>] sys_read+0x55/0xa0
[  110.782019]  [<ffffffff8173e159>] system_call_fastpath+0x16/0x1b
[  110.788028] BUG: scheduling while atomic: cat/6182/0x10000002
[  110.793774] INFO: lockdep is turned off.
[  110.797698] Modules linked in: vfat(F) fat(F) acpi_cpufreq(F) mperf(F) coretemp(F) kvm_intel(F) kvm(F) crc32c_intel(F) iTCO_wdt(F) cdc_ether(F) iTCO_vendor_support(F) usbnet(F) shpchp(F) i7core_edac(F) ioatdma(F) mii(F) lpc_ich(F) microcode(F) serio_raw(F) edac_core(F) dca(F) i2c_i801(F) mfd_core(F) bnx2(F) mgag200(F) i2c_algo_bit(F) mptsas(F) drm_kms_helper(F) mptscsih(F) ttm(F) mptbase(F) drm(F) scsi_transport_sas(F) i2c_core(F)
[  110.836505] irq event stamp: 0
[  110.839564] hardirqs last  enabled at (0): [<          (null)>]           (null)
[  110.846978] hardirqs last disabled at (0): [<ffffffff81068218>] copy_process.part.22+0x5e8/0x1650
[  110.855868] softirqs last  enabled at (0): [<ffffffff81068218>] copy_process.part.22+0x5e8/0x1650
[  110.864755] softirqs last disabled at (0): [<          (null)>]           (null)
[  110.872173] Pid: 6182, comm: cat Tainted: GF     D W    3.9.0-0.rc6.git2.1.eficheck.fc19.x86_64 #1
[  110.881129] Call Trace:
[  110.883580]  [<ffffffff810da610>] ? print_irqtrace_events+0xd0/0xe0
[  110.889853]  [<ffffffff81727ce1>] __schedule_bug+0x68/0x78
[  110.895342]  [<ffffffff817322e1>] __schedule+0x9c1/0xa20
[  110.900660]  [<ffffffff810a82aa>] __cond_resched+0x2a/0x40
[  110.906150]  [<ffffffff817323bf>] _cond_resched+0x2f/0x40
[  110.911551]  [<ffffffff8173151f>] down_read+0x2f/0x98
[  110.916604]  [<ffffffff81084a34>] exit_signals+0x24/0x130
[  110.922005]  [<ffffffff81070bed>] do_exit+0xbd/0xc90
[  110.926974]  [<ffffffff8106df18>] ? kmsg_dump+0x1b8/0x240
[  110.932374]  [<ffffffff8106dd85>] ? kmsg_dump+0x25/0x240
[  110.937690]  [<ffffffff81735f83>] oops_end+0xa3/0xf0
[  110.942660]  [<ffffffff8101eb18>] die+0x58/0x90
[  110.947193]  [<ffffffff817359b2>] do_general_protection+0xe2/0x170
[  110.953377]  [<ffffffff81735023>] ? restore_args+0x30/0x30
[  110.958864]  [<ffffffff81735298>] general_protection+0x28/0x30
[  110.964700]  [<ffffffff8137ca70>] ? do_raw_spin_lock+0x150/0x150
[  110.970711]  [<ffffffff8173407a>] ? _raw_spin_lock_irq+0x5a/0x90
[  110.976722]  [<ffffffff8159f233>] ? efivarfs_file_read+0x53/0x180
[  110.982816]  [<ffffffff8159f233>] efivarfs_file_read+0x53/0x180
[  110.988738]  [<ffffffff812f99a5>] ? security_file_permission+0x95/0xb0
[  110.995269]  [<ffffffff811e0f4c>] vfs_read+0xac/0x180
[  111.000322]  [<ffffffff811e11d5>] sys_read+0x55/0xa0
[  111.005292]  [<ffffffff8173e159>] system_call_fastpath+0x16/0x1b
[  111.011493] note: cat[6182] exited with preempt_count 1
[  111.016891] BUG: scheduling while atomic: cat/6182/0x10000002
[  111.022806] INFO: lockdep is turned off.
[  111.026893] Modules linked in: vfat(F) fat(F) acpi_cpufreq(F) mperf(F) coretemp(F) kvm_intel(F) kvm(F) crc32c_intel(F) iTCO_wdt(F) cdc_ether(F) iTCO_vendor_support(F) usbnet(F) shpchp(F) i7core_edac(F) ioatdma(F) mii(F) lpc_ich(F) microcode(F) serio_raw(F) edac_core(F) dca(F) i2c_i801(F) mfd_core(F) bnx2(F) mgag200(F) i2c_algo_bit(F) mptsas(F) drm_kms_helper(F) mptscsih(F) ttm(F) mptbase(F) drm(F) scsi_transport_sas(F) i2c_core(F)
[  111.067839] Pid: 6182, comm: cat Tainted: GF     D W    3.9.0-0.rc6.git2.1.eficheck.fc19.x86_64 #1
[  111.076968] Call Trace:
[  111.079630]  [<ffffffff81727ce1>] __schedule_bug+0x68/0x78
[  111.085290]  [<ffffffff817322e1>] __schedule+0x9c1/0xa20
[  111.090779]  [<ffffffff8109a150>] ? lock_hrtimer_base.isra.19+0x30/0x60
[  111.097575]  [<ffffffff810a82aa>] __cond_resched+0x2a/0x40
[  111.103234]  [<ffffffff817323bf>] _cond_resched+0x2f/0x40
[  111.108783]  [<ffffffff8173151f>] down_read+0x2f/0x98
[  111.114010]  [<ffffffff810ef4fe>] acct_collect+0x4e/0x1b0
[  111.119591]  [<ffffffff81071496>] do_exit+0x966/0xc90
[  111.124816]  [<ffffffff8106df18>] ? kmsg_dump+0x1b8/0x240
[  111.130383]  [<ffffffff8106dd85>] ? kmsg_dump+0x25/0x240
[  111.135859]  [<ffffffff81735f83>] oops_end+0xa3/0xf0
[  111.141007]  [<ffffffff8101eb18>] die+0x58/0x90
[  111.145705]  [<ffffffff817359b2>] do_general_protection+0xe2/0x170
[  111.152069]  [<ffffffff81735023>] ? restore_args+0x30/0x30
[  111.157743]  [<ffffffff81735298>] general_protection+0x28/0x30
[  111.163756]  [<ffffffff8137ca70>] ? do_raw_spin_lock+0x150/0x150
[  111.169935]  [<ffffffff8173407a>] ? _raw_spin_lock_irq+0x5a/0x90
[  111.176114]  [<ffffffff8159f233>] ? efivarfs_file_read+0x53/0x180
[  111.182374]  [<ffffffff8159f233>] efivarfs_file_read+0x53/0x180
[  111.188469]  [<ffffffff812f99a5>] ? security_file_permission+0x95/0xb0
[  111.195161]  [<ffffffff811e0f4c>] vfs_read+0xac/0x180
[  111.200382]  [<ffffffff811e11d5>] sys_read+0x55/0xa0
[  111.205523]  [<ffffffff8173e159>] system_call_fastpath+0x16/0x1b
[  111.260541] BUG: scheduling while atomic: cat/6182/0x10000002
[  111.266449] INFO: lockdep is turned off.
[  111.270549] Modules linked in: vfat(F) fat(F) acpi_cpufreq(F) mperf(F) coretemp(F) kvm_intel(F) kvm(F) crc32c_intel(F) iTCO_wdt(F) cdc_ether(F) iTCO_vendor_support(F) usbnet(F) shpchp(F) i7core_edac(F) ioatdma(F) mii(F) lpc_ich(F) microcode(F) serio_raw(F) edac_core(F) dca(F) i2c_i801(F) mfd_core(F) bnx2(F) mgag200(F) i2c_algo_bit(F) mptsas(F) drm_kms_helper(F) mptscsih(F) ttm(F) mptbase(F) drm(F) scsi_transport_sas(F) i2c_core(F)
[  111.311337] Pid: 6182, comm: cat Tainted: GF     D W    3.9.0-0.rc6.git2.1.eficheck.fc19.x86_64 #1
[  111.320464] Call Trace:
[  111.323087]  [<ffffffff81727ce1>] __schedule_bug+0x68/0x78
[  111.328749]  [<ffffffff817322e1>] __schedule+0x9c1/0xa20
[  111.334231]  [<ffffffff810a82aa>] __cond_resched+0x2a/0x40
[  111.339914]  [<ffffffff817323bf>] _cond_resched+0x2f/0x40
[  111.345499]  [<ffffffff8119c3cb>] remove_vma+0x2b/0x80
[  111.350788]  [<ffffffff8119f72c>] exit_mmap+0xec/0x170
[  111.356097]  [<ffffffff810672bb>] mmput+0x8b/0xf0
[  111.360965]  [<ffffffff81070dc1>] do_exit+0x291/0xc90
[  111.366193]  [<ffffffff8106df18>] ? kmsg_dump+0x1b8/0x240
[  111.371778]  [<ffffffff8106dd85>] ? kmsg_dump+0x25/0x240
[  111.377260]  [<ffffffff81735f83>] oops_end+0xa3/0xf0
[  111.382385]  [<ffffffff8101eb18>] die+0x58/0x90
[  111.387081]  [<ffffffff817359b2>] do_general_protection+0xe2/0x170
[  111.393419]  [<ffffffff81735023>] ? restore_args+0x30/0x30
[  111.399075]  [<ffffffff81735298>] general_protection+0x28/0x30
[  111.405083]  [<ffffffff8137ca70>] ? do_raw_spin_lock+0x150/0x150
[  111.411258]  [<ffffffff8173407a>] ? _raw_spin_lock_irq+0x5a/0x90
[  111.417442]  [<ffffffff8159f233>] ? efivarfs_file_read+0x53/0x180
[  111.423710]  [<ffffffff8159f233>] efivarfs_file_read+0x53/0x180
[  111.429800]  [<ffffffff812f99a5>] ? security_file_permission+0x95/0xb0
[  111.436495]  [<ffffffff811e0f4c>] vfs_read+0xac/0x180
[  111.441717]  [<ffffffff811e11d5>] sys_read+0x55/0xa0
[  111.446854]  [<ffffffff8173e159>] system_call_fastpath+0x16/0x1b
Segmentation fault

.eficheck is just Fedoar 19 3.9-rc6 kernel with Matthew's patchset:

efi: Determine how much space is used by boot services-only variables.
...

Eariler log was messed up while further reproduction was blocked without
the patchset. The call traces are the same though.


Lingzhu Xiang