bisecting cause commit starting from a99163e9e708d5d773b7de6da952fcddc341f977
building syzkaller on c26fb06b75e80ff45e13dc5cc575c8490c44411d
testing commit a99163e9e708d5d773b7de6da952fcddc341f977 with gcc (GCC) 10.2.1 20210217
kernel signature: 09de208bc5aefa701aec476392d300866e617285f6d1e2087c8fcc67ec62ff54
all runs: crashed: general protection fault in vmx_vcpu_run
testing release v5.11
testing commit f40ddce88593482919761f74910f42f4b84c004b with gcc (GCC) 10.2.1 20210217
kernel signature: ad89032f561d24add2f01d30d37d5dcc4ee55a3084c05b5f06c702f9f142ff84
all runs: OK
# git bisect start a99163e9e708d5d773b7de6da952fcddc341f977 f40ddce88593482919761f74910f42f4b84c004b
Bisecting: 4263 revisions left to test after this (roughly 12 steps)
[5bbb336ba75d95611a7b9456355b48705016bdb1] Merge tag 'for-5.12/io_uring-2021-02-17' of git://git.kernel.dk/linux-block

testing commit 5bbb336ba75d95611a7b9456355b48705016bdb1 with gcc (GCC) 10.2.1 20210217
kernel signature: 9b9e26cb0bd2cc3c870ac35269cae533df10b819700fc67f538823937a7dae97
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
reproducer seems to be flaky
# git bisect bad 5bbb336ba75d95611a7b9456355b48705016bdb1
Bisecting: 2232 revisions left to test after this (roughly 11 steps)
[56bf6fc266ca14d2b9276c8a62e4ff6783bfe68b] Merge tag 'arm-defconfig-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

testing commit 56bf6fc266ca14d2b9276c8a62e4ff6783bfe68b with gcc (GCC) 10.2.1 20210217
kernel signature: fe4a58ce951519af06404db5350574cac75736eb43a3a7422c4c75e26193e265
all runs: OK
# git bisect good 56bf6fc266ca14d2b9276c8a62e4ff6783bfe68b
Bisecting: 1037 revisions left to test after this (roughly 10 steps)
[780607b9731feef575514108fc7956c54180f16e] Merge tag 'usb-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

testing commit 780607b9731feef575514108fc7956c54180f16e with gcc (GCC) 10.2.1 20210217
kernel signature: 3c84fde7ac0d27cd3988cd7f45611caa42ebed8faef204acb27039148fa006d3
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 780607b9731feef575514108fc7956c54180f16e
Bisecting: 590 revisions left to test after this (roughly 9 steps)
[889231c6c80113ad0929eea01e8272048be38552] Merge tag 'v5.12-rockchip-dts64-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip into arm/dt

testing commit 889231c6c80113ad0929eea01e8272048be38552 with gcc (GCC) 10.2.1 20210217
kernel signature: bbc1061069916e93cecec44a7a3fc9530b51d152dc6d2415752536afd70b7596
all runs: OK
# git bisect good 889231c6c80113ad0929eea01e8272048be38552
Bisecting: 291 revisions left to test after this (roughly 8 steps)
[c85bfed171aaa91a32dcecd7962a4c880bf9d0ab] Merge tag 'usb-serial-5.12-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next

testing commit c85bfed171aaa91a32dcecd7962a4c880bf9d0ab with gcc (GCC) 10.2.1 20210217
kernel signature: c8eabab195f3b52a9fa208ccee4d07c3764d438f6259e270328b74d50df3a39b
all runs: OK
# git bisect good c85bfed171aaa91a32dcecd7962a4c880bf9d0ab
Bisecting: 144 revisions left to test after this (roughly 7 steps)
[3e89c7ea7a828fec5694101e0f0ff7240e634470] Merge tag 'ras_updates_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

testing commit 3e89c7ea7a828fec5694101e0f0ff7240e634470 with gcc (GCC) 10.2.1 20210217
kernel signature: 7fe8404ee3ac33b3149384bb1dacce5280ad2005cb3a22769200cd37e050f595
all runs: OK
# git bisect good 3e89c7ea7a828fec5694101e0f0ff7240e634470
Bisecting: 71 revisions left to test after this (roughly 6 steps)
[26a30ffff952390499a95a0accad0c49379e5301] Merge tag 'x86_build_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

testing commit 26a30ffff952390499a95a0accad0c49379e5301 with gcc (GCC) 10.2.1 20210217
kernel signature: f6ec3cd021b5e15c6aea78191f2b9a5fef6df0721dc943ff7b922b29816a19c5
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 26a30ffff952390499a95a0accad0c49379e5301
Bisecting: 45 revisions left to test after this (roughly 5 steps)
[1255f44017c02d14e3ad5b63cdf619a734d765a1] Merge tag 'x86_paravirt_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

testing commit 1255f44017c02d14e3ad5b63cdf619a734d765a1 with gcc (GCC) 10.2.1 20210217
kernel signature: af04a4afc5065912c4bd1a39f0932f76d9fdf4149d2f4566a962986e66d8705e
all runs: OK
# git bisect good 1255f44017c02d14e3ad5b63cdf619a734d765a1
Bisecting: 21 revisions left to test after this (roughly 5 steps)
[40c1fa52cdb7c13ef88232e374b4b8ac8d820c4f] Merge branch 'x86/cleanups' into x86/mm

testing commit 40c1fa52cdb7c13ef88232e374b4b8ac8d820c4f with gcc (GCC) 10.2.1 20210217
kernel signature: 6bcaca6bdb06f42a65e9b608dd5fafbd8a9a5d1d0d173725fd033c5ff21a4b35
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 40c1fa52cdb7c13ef88232e374b4b8ac8d820c4f
Bisecting: 11 revisions left to test after this (roughly 4 steps)
[66fcd98883816dba3b66da20b5fc86fa410638b5] x86/fault: Don't look for extable entries for SMEP violations

testing commit 66fcd98883816dba3b66da20b5fc86fa410638b5 with gcc (GCC) 10.2.1 20210217
kernel signature: 2bca92fd3efb740b3c6e5e66635eb4eb9f05e752dc02dd66da512164dbbc5e67
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 66fcd98883816dba3b66da20b5fc86fa410638b5
Bisecting: 5 revisions left to test after this (roughly 3 steps)
[ef2544fb3f6457b79fc73cea39dafd67ee0f2824] x86/fault: Document the locking in the fault_signal_pending() path

testing commit ef2544fb3f6457b79fc73cea39dafd67ee0f2824 with gcc (GCC) 10.2.1 20210217
kernel signature: 995b1e3e877fb6dd4119804b97e35449c5e644e77546bc161bae884a32ca652c
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad ef2544fb3f6457b79fc73cea39dafd67ee0f2824
Bisecting: 2 revisions left to test after this (roughly 2 steps)
[d24df8ecf9b6f81029f520ae7158a8670a28d70b] x86/fault: Skip the AMD erratum #91 workaround on unaffected CPUs

testing commit d24df8ecf9b6f81029f520ae7158a8670a28d70b with gcc (GCC) 10.2.1 20210217
kernel signature: 8b2fad31761d90fe9e2a381d8b2ab618b6af00cd0e9f7b0466a46337d6b7c129
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad d24df8ecf9b6f81029f520ae7158a8670a28d70b
Bisecting: 0 revisions left to test after this (roughly 1 step)
[35f1c89b0cce247bf0213df243ed902989b1dcda] x86/fault: Fix AMD erratum #91 errata fixup for user code

testing commit 35f1c89b0cce247bf0213df243ed902989b1dcda with gcc (GCC) 10.2.1 20210217
kernel signature: 1e7831ff24a2d7be01990ff4df4f7fdc91463dbd952004cd8a38fd0e8a9ee8b4
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 35f1c89b0cce247bf0213df243ed902989b1dcda
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[167dcfc08b0b1f964ea95d410aa496fd78adf475] x86/mm: Increase pgt_buf size for 5-level page tables

testing commit 167dcfc08b0b1f964ea95d410aa496fd78adf475 with gcc (GCC) 10.2.1 20210217
kernel signature: 35e1b2488a54b2f195f354e1ee49592c078928fbbf7889f3ba0dd87154db1e87
run #0: crashed: SYZFAIL: wrong response packet
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
# git bisect bad 167dcfc08b0b1f964ea95d410aa496fd78adf475
167dcfc08b0b1f964ea95d410aa496fd78adf475 is the first bad commit
commit 167dcfc08b0b1f964ea95d410aa496fd78adf475
Author: Lorenzo Stoakes <lstoakes@gmail.com>
Date:   Tue Dec 15 20:56:41 2020 +0000

    x86/mm: Increase pgt_buf size for 5-level page tables
    
    pgt_buf is used to allocate page tables on initial direct page mapping
    which bootstraps the kernel into being able to allocate these before the
    direct mapping makes further pages available.
    
    INIT_PGD_PAGE_COUNT is set to 6 pages (doubled for KASLR) - 3 (PUD, PMD,
    PTE) for the 1 MiB ISA mapping and 3 more for the first direct mapping
    assignment in each case providing 2 MiB of address space.
    
    This has not been updated for 5-level page tables which has an
    additional P4D page table level above PUD.
    
    In most instances, this will not have a material impact as the first
    4 page levels allocated for the ISA mapping will provide sufficient
    address space to encompass all further address mappings.
    
    If the first direct mapping is within 512 GiB of the ISA mapping, only
    a PMD and PTE needs to be added in the instance the kernel is using 4
    KiB page tables (e.g. CONFIG_DEBUG_PAGEALLOC is enabled) and only a PMD
    if the kernel can use 2 MiB pages (the first allocation is limited to
    PMD_SIZE so a GiB page cannot be used there).
    
    However, if the machine has more than 512 GiB of RAM and the kernel is
    allocating 4 KiB page size, 3 further page tables are required.
    
    If the machine has more than 256 TiB of RAM at 4 KiB or 2 MiB page size,
    further 3 or 4 page tables are required respectively.
    
    Update INIT_PGD_PAGE_COUNT to reflect this.
    
     [ bp: Sanitize text into passive voice without ambiguous personal pronouns. ]
    
    Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
    Signed-off-by: Borislav Petkov <bp@suse.de>
    Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    Acked-by: Dave Hansen <dave.hansen@intel.com>
    Link: https://lkml.kernel.org/r/20201215205641.34096-1-lstoakes@gmail.com

 arch/x86/mm/init.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

parent commit e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62 wasn't tested
testing commit e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62 with gcc (GCC) 10.2.1 20210217
kernel signature: bbc1061069916e93cecec44a7a3fc9530b51d152dc6d2415752536afd70b7596
culprit signature: 35e1b2488a54b2f195f354e1ee49592c078928fbbf7889f3ba0dd87154db1e87
parent  signature: bbc1061069916e93cecec44a7a3fc9530b51d152dc6d2415752536afd70b7596
Reproducer flagged being flaky
revisions tested: 16, total time: 4h21m40.667438029s (build: 1h56m58.108023942s, test: 2h23m17.864735158s)
first bad commit: 167dcfc08b0b1f964ea95d410aa496fd78adf475 x86/mm: Increase pgt_buf size for 5-level page tables
recipients (to): ["bp@suse.de" "dave.hansen@intel.com" "kirill.shutemov@linux.intel.com" "lstoakes@gmail.com"]
recipients (cc): []
crash: SYZFAIL: wrong response packet
2021/02/23 23:03:48 result: hanged=false err=executor 5: failed to write control pipe: write |1: broken pipe
 (errno 16: Device or resource busy)
SYZFAIL: wrong response packet
loop exited with status 67
2021/02/23 23:03:51 executed programs: 33
2021/02/23 23:03:56 executed programs: 177