Re: Current Linus tree protection fault in __kmalloc

[Ming Lei]

On Mon, Feb 3, 2020 at 9:23 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
> On Mon, Feb 03, 2020 at 06:47:03PM +0800, Ming Lei wrote:
> > On Mon, Feb 3, 2020 at 9:29 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> > >
> > > Anyone else seeing this?  My poor laptop has little compile grunt.
> >
> > It can be triggered in my VM every time, and has started git-bisect already.
>
> Glad to know it's not just me.  I finished a git bisect, but it
> pointed to a nonsense commit:
>
> git bisect start
> # bad: [a8ad62c76e8d082aa5fc3f2bd9f65d13ff2d5e8a] iomap: Convert from readpages to readahead
> git bisect bad a8ad62c76e8d082aa5fc3f2bd9f65d13ff2d5e8a
> # good: [d5226fa6dbae0569ee43ecfc08bdcd6770fc4755] Linux 5.5
> git bisect good d5226fa6dbae0569ee43ecfc08bdcd6770fc4755
> # good: [aac96626713fe167c672f9a008be0f514aa3e237] Merge tag 'usb-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
> git bisect good aac96626713fe167c672f9a008be0f514aa3e237
> # good: [d47c7f06268082bc0082a15297a07c0da59b0fc4] Merge branch 'linux-5.6' of git://github.com/skeggsb/linux into drm-next
> git bisect good d47c7f06268082bc0082a15297a07c0da59b0fc4
> # bad: [4cadc60d6bcfee9c626d4b55e9dc1475d21ad3bb] Merge tag 'for-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply
> git bisect bad 4cadc60d6bcfee9c626d4b55e9dc1475d21ad3bb
> # bad: [701a9c8092ddf299d7f90ab2d66b19b4526d1186] Merge tag 'char-misc-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
> git bisect bad 701a9c8092ddf299d7f90ab2d66b19b4526d1186
> # good: [270f104ba26f0498aff85e5b002e2f4c2249c04b] staging: wfx: update TODO
> git bisect good 270f104ba26f0498aff85e5b002e2f4c2249c04b
> # good: [ca9b5b6283984f67434cee810f3b08e19630226d] Merge tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
> git bisect good ca9b5b6283984f67434cee810f3b08e19630226d
> # good: [10d3e38c7923853967cea97513213bba923dde64] Merge tag 'icc-5.6-rc1' of https://git.linaro.org/people/georgi.djakov/linux into char-misc-next
> git bisect good 10d3e38c7923853967cea97513213bba923dde64
> # good: [b5909c6d16fd4e3972b0cd48dedde08d55575342] staging: kpc2000: rename variables with kpc namespace
> git bisect good b5909c6d16fd4e3972b0cd48dedde08d55575342
> # good: [72a9cc952f123948ca1d1011a12e5e1312140b68] devtmpfs: factor out common tail of devtmpfs_{create,delete}_node
> git bisect good 72a9cc952f123948ca1d1011a12e5e1312140b68
> # good: [2485055394be272d098ca7dd63193d5041fb8140] staging: most: core: drop device reference
> git bisect good 2485055394be272d098ca7dd63193d5041fb8140
> # good: [7ba31c3f2f1ee095d8126f4d3757fc3b2bc3c838] Merge tag 'staging-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
> git bisect good 7ba31c3f2f1ee095d8126f4d3757fc3b2bc3c838
> # bad: [0db4a15d4c2787b1112001790d4f95bd2c5fed6f] mei: me: add jasper point DID
> git bisect bad 0db4a15d4c2787b1112001790d4f95bd2c5fed6f
> # bad: [987f028b8637cfa7658aa456ae73f8f21a7a7f6f] char: hpet: Use flexible-array member
> git bisect bad 987f028b8637cfa7658aa456ae73f8f21a7a7f6f
> # bad: [eb143f8756e77c8fcfc4d574922ae9efd3a43ca9] binder: fix log spam for existing debugfs file creation.
> git bisect bad eb143f8756e77c8fcfc4d574922ae9efd3a43ca9
> # first bad commit: [eb143f8756e77c8fcfc4d574922ae9efd3a43ca9] binder: fix log spam for existing debugfs file creation.
>
> The .config doesn't even have the binder enabled, which is the only file
> touched in the commit.
>

My git bisect is just done, and it points to the following commit:

commit 987f028b8637cfa7658aa456ae73f8f21a7a7f6f
Author: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Date:   Mon Jan 20 17:53:26 2020 -0600

    char: hpet: Use flexible-array member

I have double checked the commit, and looks it is really the 1st bad one.

Thanks,
Ming Lei