Found can not accessing efi variables through efivarfs after hibernate resume.
This issue can reproduce on Intel DQ57TM machine and Acer Gateway Z5WT2 UEFI
notebook on my hand:
[ 160.007691] BUG: unable to handle kernel paging request at fffffffefcc44e60
[ 160.014705] IP: [<ffffffff8146618d>] virt_efi_get_variable+0x5d/0xa0
[ 160.021091] PGD 1a0c067 PUD 1370ae063 PMD 1370bd063 PTE 0
[ 160.026562] Oops: 0000 [#1] SMP
[ 160.029830] Modules linked in: bridge(E) stp(E) llc(E) iscsi_ibft(E)
iscsi_boot_sysfs(E) af_packet(E) nls_iso8859_1(E) nls_cp437(E)
intel_powerclamp(E) coretemp(E) kvm_intel(E) vfat(E) fat(E) kvm(E) iTCO_wdt(
[ 160.102481] CPU: 0 PID: 1659 Comm: cat Tainted: G E
4.2.0-rc2-default+ #93
[ 160.110584] Hardware name: Intel Corp. Intel(R) UDK2010 firmware developer
platform, BIOS SDV.TM.B13 Release Build (CSM Available) 07/03/2013
[ 160.123280] task: ffff88013607d380 ti: ffff880136794000 task.ti:
ffff880136794000
[ 160.130772] RIP: 0010:[<ffffffff8146618d>] [<ffffffff8146618d>]
virt_efi_get_variable+0x5d/0xa0
[ 160.139590] RSP: 0018:ffff880136797d78 EFLAGS: 00010096
[ 160.144910] RAX: fffffffefcc44e18 RBX: 0000000000000092 RCX:
0000000000000000
[ 160.152047] RDX: ffff88013647b400 RSI: ffff88013647b000 RDI:
ffff88000009cff8
[ 160.159184] RBP: ffff880136797db8 R08: ffff880136797e00 R09:
0000000000000000
[ 160.166320] R10: 00007ffecdaf7e30 R11: 0000000000000246 R12:
ffff88013647b000
[ 160.173459] R13: ffff88013647b400 R14: 0000000000000000 R15:
ffff880136797e00
[ 160.180597] FS: 00007f4bdbbc4700(0000) GS:ffff88013bc00000(0000)
knlGS:0000000000000000
[ 160.188691] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 160.194444] CR2: fffffffefcc44e60 CR3: 00000000b9f7c000 CR4:
00000000000007f0
[ 160.201580] Stack:
[ 160.203600] 0000000200000002 0000000000000000 ffff880136797e50
ffff88013647b000
[ 160.211075] ffff880136797e00 ffffffff81f5c960 ffff880136797f20
0000000000000fff
[ 160.218551] ffff880136797de8 ffffffff81462325 ffff880136797de8
ffff88013647b000
[ 160.226025] Call Trace:
[ 160.228486] [<ffffffff81462325>] efivar_entry_size+0x45/0xe0
[ 160.234246] [<ffffffffa006364a>] efivarfs_file_read+0x3a/0xf0 [efivarfs]
[ 160.241043] [<ffffffff811ca938>] __vfs_read+0x28/0xd0
[ 160.246193] [<ffffffff81260303>] ? security_file_permission+0xa3/0xc0
[ 160.252730] [<ffffffff811cae76>] ? rw_verify_area+0x56/0xe0
[ 160.258394] [<ffffffff811caf86>] vfs_read+0x86/0x130
[ 160.263448] [<ffffffff811cbd86>] SyS_read+0x46/0xa0
[ 160.268421] [<ffffffff81592c6e>] entry_SYSCALL_64_fastpath+0x12/0x71
[ 160.274869] Code: 48 89 c3 e8 c6 51 bf ff e8 11 7e ba ff 48 8b 05 8a 45 6c
00 4c 8b 45 c8 4c 89 e6 4c 89 f1 4c 89 ea 48 8b 40 58 4d 89 c1 4d 89 f8 <48> 8b
78 48 31 c0 e8 88 52 bf ff 49 89 c4 e8 00 7f ba ff 48
[ 160.294855] RIP [<ffffffff8146618d>] virt_efi_get_variable+0x5d/0xa0
[ 160.301326] RSP <ffff880136797d78>
[ 160.304821] CR2: fffffffefcc44e60
[ 160.308144] ---[ end trace b0019dfbfd15b720 ]---
[ 160.312999] ------------[ cut here ]------------
[ 160.317647] WARNING: CPU: 0 PID: 1383 at arch/x86/kernel/fpu/core.c:41
kernel_fpu_disable+0x38/0x50()
[ 160.317693] Modules linked in: bridge(E) stp(E) llc(E) iscsi_ibft(E)
iscsi_boot_sysfs(E) af_packet(E) nls_iso8859_1(E) nls_cp437(E)
intel_powerclamp(E) coretemp(E) kvm_intel(E) vfat(E) fat(E) kvm(E) iTCO_wdt(
[ 160.317699] CPU: 0 PID: 1383 Comm: bash Tainted: G D E
4.2.0-rc2-default+ #93
[ 160.317701] Hardware name: Intel Corp. Intel(R) UDK2010 firmware developer
platform, BIOS SDV.TM.B13 Release Build (CSM Available) 07/03/2013
[ 160.317704] ffffffff8180618c ffff8800b965bea8 ffffffff8158cb70
0000000000000001
[ 160.317707] 0000000000000000 ffff8800b965bee8 ffffffff81064bbc
ffff8800ba651e48
[ 160.317709] ffff88003f5e6440 000000000048140a 0000000002207580
000000000000004c
[ 160.317710] Call Trace:
[ 160.317718] [<ffffffff8158cb70>] dump_stack+0x45/0x57
[ 160.317727] [<ffffffff81064bbc>] warn_slowpath_common+0x8c/0xd0
[ 160.317729] [<ffffffff81064cba>] warn_slowpath_null+0x1a/0x20
[ 160.317731] [<ffffffff8100dde8>] kernel_fpu_disable+0x38/0x50
[ 160.317734] [<ffffffff8100e19d>] fpu__restore+0x1d/0x110
[ 160.317738] [<ffffffff81011e03>] ? syscall_trace_leave+0x93/0xf0
[ 160.317741] [<ffffffff81004013>] do_device_not_available+0x33/0x40
[ 160.317746] [<ffffffff8159459e>] device_not_available+0x1e/0x30
[ 160.317748] ---[ end trace b0019dfbfd15b721 ]---
Procedure for reproducing issue:
+ Running hibernate, press power button to resume machine.
+ After resumed, running cat or hexdump any efi variable through efivarfs.
e.g.
cat
/sys/firmware/efi/efivars/SecureBoot-8be4df61-93ca-11d2-aa0d-00e098032b8c
Then got the above kernel oops