Re: Crash in -next due to 'MIPS: Move FP usage checks into protected_{save, restore}_fp_context'

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Jul 15, 2015 at 09:09:18AM -0700, Guenter Roeck wrote:
> Hi,
> 
> my qemu test for mipsel crashes with next-20150715 as follows.
> 
ping ... problem is still seen as of next-20150727.

> ...
> Btrfs loaded
> console [netcon0] enabled
> netconsole: network logging started
> Freeing unused kernel memory: 284K (808f9000 - 80940000)
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000008
> 
> Bisect points to commit 'MIPS: Move FP usage checks into protected_{save,
> restore}_fp_context'. Bisect log is as follows.
> 
> The problem is not seen with bit endian qemu test.
> 
> Please let me know if there is anything I can do to help debugging
> this problem.
> 
> Thanks,
> Guenter
> ---
> 
> # bad: [f4d61b2d73c1e4964ad68df238af5005485469af] Add linux-next specific files for 20150715
> # good: [bc0195aad0daa2ad5b0d76cce22b167bc3435590] Linux 4.2-rc2
> git bisect start 'HEAD' 'v4.2-rc2'
> # bad: [897f492ee766d354b949f3838cbfda8978cfd3cd] Merge remote-tracking branch 'crypto/master'
> git bisect bad 897f492ee766d354b949f3838cbfda8978cfd3cd
> # bad: [687fe9993e4fbe728113086eb9525360465694e6] Merge remote-tracking branch 'mips/mips-for-linux-next'
> git bisect bad 687fe9993e4fbe728113086eb9525360465694e6
> # good: [a06e5ae4e8d6d5846809e94d0d45afcc5a9eaf35] Merge remote-tracking branch 'omap/for-next'
> git bisect good a06e5ae4e8d6d5846809e94d0d45afcc5a9eaf35
> # good: [badbfaedef0876d3cffb3264512aaec8cc162c61] Merge remote-tracking branch 'tegra/for-next'
> git bisect good badbfaedef0876d3cffb3264512aaec8cc162c61
> # bad: [88841d986cebe1207a47cd7422f5069b2616b194] MIPS: Advertise MSA support via HWCAP when present
> git bisect bad 88841d986cebe1207a47cd7422f5069b2616b194
> # good: [7c1f7b83170bc14a3e461a9b5595fcecf857da70] MIPS: octeon: Replace the homebrewn flow handler
> git bisect good 7c1f7b83170bc14a3e461a9b5595fcecf857da70
> # good: [186a699fdf6f0866ca980bcf5e79f54922fe52c2] MIPS: Introduce accessors for MSA vector registers
> git bisect good 186a699fdf6f0866ca980bcf5e79f54922fe52c2
> # bad: [1793cdaa84ed5c4025a36793f350b07b49555b57] MIPS: Skip odd double FP registers when copying FP32 sigcontext
> git bisect bad 1793cdaa84ed5c4025a36793f350b07b49555b57
> # good: [8a6bb0ab74eaca5f2a4e60f94df2ea5b08cdfd63] MIPS: Simplify EVA FP context handling code
> git bisect good 8a6bb0ab74eaca5f2a4e60f94df2ea5b08cdfd63
> # good: [6f47ebd751531249fe0e2b4d3afdfcbf9f66dbd8] MIPS: Use struct mips_abi offsets to save FP context
> git bisect good 6f47ebd751531249fe0e2b4d3afdfcbf9f66dbd8
> # bad: [fa3156ca734cb65f23df0f844433e75ea1da37f3] MIPS: Move FP usage checks into protected_{save, restore}_fp_context
> git bisect bad fa3156ca734cb65f23df0f844433e75ea1da37f3
> # first bad commit: [fa3156ca734cb65f23df0f844433e75ea1da37f3] MIPS: Move FP usage checks into protected_{save, restore}_fp_context