bisecting cause commit starting from 7c832d2f9b959e3181370c8b0dacaf9efe13fc05
building syzkaller on 0c5d9412d774262384cbdbe9d672b077364ed776
testing commit 7c832d2f9b959e3181370c8b0dacaf9efe13fc05
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 2c741ddeb7fc67524c922aaa5c48c13160e428aae5fafa5e45db74e614c0a53b
all runs: crashed: WARNING: held lock freed in spi_unregister_controller
testing release v5.14
testing commit 7d2a07b769330c34b4deabeed939325c77a7ec2f
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: de5d0644639cc5c360c5e4129b2c3253ccb03fa29846cb1eb6936ee1da8e68ac
all runs: OK
# git bisect start 7c832d2f9b959e3181370c8b0dacaf9efe13fc05 7d2a07b769330c34b4deabeed939325c77a7ec2f
Bisecting: 10492 revisions left to test after this (roughly 13 steps)
[14e2bc4e8c40a876c1ab5597320d523c12a97f39] Merge tag 'nfsd-5.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

testing commit 14e2bc4e8c40a876c1ab5597320d523c12a97f39
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: b5ac7330f00980c4a84c1dced6473dd4592419cabd72572af26ec7f821dbbbbb
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad 14e2bc4e8c40a876c1ab5597320d523c12a97f39
Bisecting: 5251 revisions left to test after this (roughly 12 steps)
[0d290223a6c77107b1c3988959e49279a8dafaba] Merge tag 'sound-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound

testing commit 0d290223a6c77107b1c3988959e49279a8dafaba
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 40b75b20cecfa0095e800d24244cc494f94230b57763266d0e4e19a341cd5353
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad 0d290223a6c77107b1c3988959e49279a8dafaba
Bisecting: 3322 revisions left to test after this (roughly 11 steps)
[29ce8f9701072fc221d9c38ad952de1a9578f95c] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

testing commit 29ce8f9701072fc221d9c38ad952de1a9578f95c
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: f932ff6a0e00dc4a8ca50549cfa66d36f97dd32b17cf9d85e61a646e586692f1
all runs: OK
# git bisect good 29ce8f9701072fc221d9c38ad952de1a9578f95c
Bisecting: 1676 revisions left to test after this (roughly 11 steps)
[8e235ff9a1e3dc3d800224ab97bcd2418d3b19c3] Merge tag 'devprop-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

testing commit 8e235ff9a1e3dc3d800224ab97bcd2418d3b19c3
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 39b8e4c8ff66ef0b447a8e2311388fb4c607e24890b2d3728403dd96f88ff898
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad 8e235ff9a1e3dc3d800224ab97bcd2418d3b19c3
Bisecting: 843 revisions left to test after this (roughly 10 steps)
[8596e589b787732c8346f0482919e83cc9362db1] Merge tag 'timers-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

testing commit 8596e589b787732c8346f0482919e83cc9362db1
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: a71652bc6ff5bbc84336a83dd5a2bc43f501ffa369476ff60561aa6422368cb1
all runs: OK
# git bisect good 8596e589b787732c8346f0482919e83cc9362db1
Bisecting: 303 revisions left to test after this (roughly 9 steps)
[e24c567b7ecff1c8b6023a10d7f78256cef742c4] Merge tag '5.15-rc-first-ksmbd-merge' of git://git.samba.org/ksmbd

testing commit e24c567b7ecff1c8b6023a10d7f78256cef742c4
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 627e440897d33e825db41eb28859180f3b0307eb593dd9d54d7cca2c0133a41e
run #0: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #1: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #2: basic kernel testing failed: failed to copy test binary to VM: timedout ["scp" "-P" "22" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "BatchMode=yes" "-o" "IdentitiesOnly=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/bin/linux_amd64/syz-executor" "root@10.128.1.91:./syz-executor"]
Warning: Permanently added '10.128.1.91' (ECDSA) to the list of known hosts.

run #3: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #4: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #5: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #6: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #7: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #8: crashed: KFENCE: use-after-free in kvm_fastop_exception
run #9: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad e24c567b7ecff1c8b6023a10d7f78256cef742c4
Bisecting: 262 revisions left to test after this (roughly 8 steps)
[c547d89a9a445f6bb757b93247de43d312e722da] Merge tag 'for-5.15/io_uring-2021-08-30' of git://git.kernel.dk/linux-block

testing commit c547d89a9a445f6bb757b93247de43d312e722da
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: b8f56bb910e393fcc2a345c4d780615c0a371d2775d7b053662f6bbc19199b33
all runs: OK
# git bisect good c547d89a9a445f6bb757b93247de43d312e722da
Bisecting: 131 revisions left to test after this (roughly 7 steps)
[6f3d5eeec744727bf017be3bb12e7fbf1c4438ed] ksmbd: use list_for_each_entry instead of list_for_each

testing commit 6f3d5eeec744727bf017be3bb12e7fbf1c4438ed
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: a0529ae78adb97cee7ca3a0d3cfbc5011a3e4f86db0f3c5f235ebbf0ba7cfb1c
all runs: OK
# git bisect good 6f3d5eeec744727bf017be3bb12e7fbf1c4438ed
Bisecting: 65 revisions left to test after this (roughly 6 steps)
[af320a739029f6f8c5c05e769fadaf88e9b7d34f] ksmbd: add negotiate context verification

testing commit af320a739029f6f8c5c05e769fadaf88e9b7d34f
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: a0529ae78adb97cee7ca3a0d3cfbc5011a3e4f86db0f3c5f235ebbf0ba7cfb1c
all runs: OK
# git bisect good af320a739029f6f8c5c05e769fadaf88e9b7d34f
Bisecting: 37 revisions left to test after this (roughly 5 steps)
[456af438ad490bac7ed954cb929bcec1df7f0c82] Merge pull request #64 from namjaejeon/cifsd-for-next

testing commit 456af438ad490bac7ed954cb929bcec1df7f0c82
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: a0529ae78adb97cee7ca3a0d3cfbc5011a3e4f86db0f3c5f235ebbf0ba7cfb1c
all runs: OK
# git bisect good 456af438ad490bac7ed954cb929bcec1df7f0c82
Bisecting: 16 revisions left to test after this (roughly 4 steps)
[b91db6a0b52e019b6bdabea3f1dbe36d85c7e52c] Merge tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-block

testing commit b91db6a0b52e019b6bdabea3f1dbe36d85c7e52c
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: f40ecf8f5bf3c577af594e817cfb19bfb2a54f56f84a09b46f37028f39a1d37e
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad b91db6a0b52e019b6bdabea3f1dbe36d85c7e52c
Bisecting: 10 revisions left to test after this (roughly 3 steps)
[7a8721f84fcb3b2946a92380b6fc311e017ff02c] io_uring: add support for IORING_OP_SYMLINKAT

testing commit 7a8721f84fcb3b2946a92380b6fc311e017ff02c
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: b404a6f03081d8b33124e4f3eb1ec8fa7fc9a28ad1ddffd16abf79ef94c1754f
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad 7a8721f84fcb3b2946a92380b6fc311e017ff02c
Bisecting: 4 revisions left to test after this (roughly 2 steps)
[da2d0cede330192879e8e16ddb3158aa76ba5ec2] namei: make do_symlinkat() take struct filename

testing commit da2d0cede330192879e8e16ddb3158aa76ba5ec2
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 246f2ddd50a7b052c42fd181928734733e1cf1aeb54d2b119172ef21ce2ec6a7
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad da2d0cede330192879e8e16ddb3158aa76ba5ec2
Bisecting: 2 revisions left to test after this (roughly 1 step)
[0ee50b47532a81ab36046241822d1ecb4e08e76d] namei: change filename_parentat() calling conventions

testing commit 0ee50b47532a81ab36046241822d1ecb4e08e76d
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: e1838a17b55b0121fbde5dce2a838e4394c25fa927bf040e01dc4cee22c7d15b
all runs: boot failed: KASAN: use-after-free Read in __d_alloc
# git bisect skip 0ee50b47532a81ab36046241822d1ecb4e08e76d
Bisecting: 2 revisions left to test after this (roughly 1 step)
[584d3226d665214dc1c498045c253529acdd3134] namei: make do_mkdirat() take struct filename

testing commit 584d3226d665214dc1c498045c253529acdd3134
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 4a1e756a59a7a960003d8025ac51873485b9ece698faa5a2ea279ce1aab905c6
all runs: crashed: KFENCE: use-after-free in kvm_fastop_exception
# git bisect bad 584d3226d665214dc1c498045c253529acdd3134
Bisecting: 0 revisions left to test after this (roughly 1 step)
[91ef658fb8b82837f94ea0d45d14b5b2d2541e70] namei: ignore ERR/NULL names in putname()

testing commit 91ef658fb8b82837f94ea0d45d14b5b2d2541e70
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: cb462abe6c26235a58501bf235a79fa8a93867ffb557eb7441189fccadea7bba
all runs: OK
# git bisect good 91ef658fb8b82837f94ea0d45d14b5b2d2541e70
There are only 'skip'ped commits left to test.
The first bad commit could be any of:
0ee50b47532a81ab36046241822d1ecb4e08e76d
584d3226d665214dc1c498045c253529acdd3134
We cannot bisect more!

revisions tested: 18, total time: 4h13m17.09909537s (build: 1h56m54.324248872s, test: 2h14m36.441104935s)
bisection is inconclusive, the first bad commit could be any of:
0ee50b47532a81ab36046241822d1ecb4e08e76d
584d3226d665214dc1c498045c253529acdd3134