Hi Greg, Thanks for your patience, here is what I did. I thought I followed the instructions, any useful information? > Start working on the "master" branch and do: $ git bisect start $ git bisect good v4.19 $ git bisect bad v5.10 Bisecting: 91917 revisions left to test after this (roughly 17 steps) [386403a115f95997c2715691226e11a7b5cffcfd] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next $ git bisect good Bisecting: 46699 revisions left to test after this (roughly 16 steps) [2e63f6ce7ed2c4ff83ba30ad9ccad422289a6c63] Merge branch 'uaccess.comedi' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs $ git bisect good Bisecting: 23349 revisions left to test after this (roughly 15 steps) [0f5d0a4c01cc1b7b0590baa18809a96d45a1e278] thermal: don't make THERMAL_NETLINK 'default y' $ git bisect good Bisecting: 12085 revisions left to test after this (roughly 14 steps) [726eb70e0d34dc4bc4dada71f52bba8ed638431e] Merge tag 'char-misc-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc $ git bisect good Bisecting: 6064 revisions left to test after this (roughly 13 steps) [c8b5e2600a2cfa1cdfbecf151afd67aee227381d] io_uring: use type appropriate io_kiocb handler for double poll $ git bisect good Bisecting: 2856 revisions left to test after this (roughly 12 steps) [e533cda12d8f0e7936354bafdc85c81741f805d2] Merge tag 'armsoc-dt' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc $ git bisect good Bisecting: 1423 revisions left to test after this (roughly 11 steps) [64b609d6a60c8a54ff9c43819803e6a7861e7ed1] Merge tag 'perf-urgent-2020-11-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip $ git bisect good Bisecting: 724 revisions left to test after this (roughly 10 steps) [80e1e1761d1a9eefda4d1545f8b6c0a2e46d4e3f] Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi $ git bisect good Bisecting: 362 revisions left to test after this (roughly 9 steps) [d4e904198c5b46c140fdd04492df6ec31f1f03a5] Merge tag '5.10-rc6-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6 $ git bisect good Bisecting: 225 revisions left to test after this (roughly 8 steps) [9fca90cf28920c6d0723d7efd1eae0b0fb90309c] Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma $ git bisect good Bisecting: 115 revisions left to test after this (roughly 7 steps) [ba9c1201beaa86a773e83be5654602a0667e4a4d] mm/hugetlb: clear compound_nr before freeing gigantic pages $ git bisect good Bisecting: 62 revisions left to test after this (roughly 6 steps) [1de5d12b769017f7354e7151ce1c26eb1d9ba2e4] Merge tag 'mmc-v5.10-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc $ git bisect good Bisecting: 27 revisions left to test after this (roughly 5 steps) [7b1b868e1d9156484ccce9bf11122c053de82617] Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm $ git bisect good Bisecting: 9 revisions left to test after this (roughly 4 steps) [d2360a398f0b68722641c59aeb2623e79bd03e34] Merge tag 'block-5.10-2020-12-12' of git://git.kernel.dk/linux-block $ git bisect good Bisecting: 4 revisions left to test after this (roughly 2 steps) [29ac40cbed2bc06fa218ca25d7f5e280d3d08a25] x86/mm/mem_encrypt: Fix definition of PMD_FLAGS_DEC_WP $ git bisect good Bisecting: 2 revisions left to test after this (roughly 1 step) [190113b4c6531c8e09b31d5235f9b5175cbb0f72] x86/apic/vector: Fix ordering in vector assignment $ git bisect good Bisecting: 0 revisions left to test after this (roughly 1 step) [ec6f5e0e5ca0764b4bc522c9f9d5abf876a0e3e3] Merge tag 'x86-urgent-2020-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip $ git bisect good 2c85ebc57b3e1817b6ce1a6b703928e113a90442 is the first bad commit commit 2c85ebc57b3e1817b6ce1a6b703928e113a90442 Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Date: Sun Dec 13 14:41:30 2020 -0800 Linux 5.10 :100644 100644 9ec53d947628d4dd919f84f348ab8223ef69b4e3 e30cf02da8b892f3fc95492635f426b8383e5980 M Makefile $ git bisect bad ec6f5e0e5ca0764b4bc522c9f9d5abf876a0e3e3 was both good and bad