On Sat, 2013-03-23 at 02:16 +0000, Ben Hutchings wrote: > Commit 68d929862e29 'efi: be more paranoid about available space when > creating variables' caused a regression on my EFI-booting desktop. > (I'm actually testing on 3.2.41 with several more fixes backported, but > this shouldn't matter.) > > The meaningful DMI IDs for this system are: > > /sys/devices/virtual/dmi/id/bios_date:08/22/2012 > /sys/devices/virtual/dmi/id/bios_vendor:American Megatrends Inc. > /sys/devices/virtual/dmi/id/bios_version:4003 > /sys/devices/virtual/dmi/id/board_name:P8Z68-V LX > /sys/devices/virtual/dmi/id/board_vendor:ASUSTeK Computer INC. > > It is no longer possible to write any variables; this always fails with > -ENOSPC. (It also wasn't possible to delete variables - but I > introduced that bug in backporting.) With some extra debug logging I > found that query_variable_information yielded: > > storage_size = 65536 > remaining_size = 23760 > max_size = 23734 > > This is not full enough to trigger garbage collection; in fact > remaining_size and max_size continue to drop by 36 bytes after each > reboot as the BIOS is updating the variable > MonotonicCounter-8be4df61-93ca-11d2-aa0d-00e098032b8c. > > 13 reboots later I had: > > remaining_size = 23292 > > I removed the size check and triggered a panic, which uses about 12K in > dump variables. After rebooting I had: [...] Actually this is not correct. It uses about 24K, as triggering a panic through magic sysrq produces an oops followed by a panic. I experimented further with just the 50% full check removed: [ 20.444442] register_efivars: resources: 65536/39843/39817 After triggering panic: [ 20.456271] register_efivars: resources: 65536/15446/15420 After triggering another panic, this time hitting the size > remaining_size check: [ 20.233869] register_efivars: resources: 65536/582/556 After a few more reboots: [ 20.778386] register_efivars: resources: 65536/42/16 One more reboot: [ 21.132836] register_efivars: resources: 65536/43092/43066 So it looks like we may actually have to disable all the size checks on this firmware! Ben. -- Ben Hutchings Who are all these weirdos? - David Bowie, about L-Space IRC channel #afp
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