bisecting fixing commit since ea4424be16887a37735d6550cfd0611528dbe5d9 building syzkaller on 7bdd8b2c56b883af3e65b261cd7c942104dc2ecc testing commit ea4424be16887a37735d6550cfd0611528dbe5d9 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: db68957f0ff90b2d54520fc5be4aa8953e257e7d51a79f5771e5d2b12271e1d5 run #0: crashed: INFO: task hung in synchronize_rcu run #1: crashed: INFO: task hung in synchronize_rcu run #2: crashed: INFO: task hung in synchronize_rcu run #3: crashed: INFO: task hung in synchronize_rcu run #4: crashed: INFO: task hung in synchronize_rcu run #5: crashed: INFO: task hung in synchronize_rcu run #6: crashed: INFO: task hung in synchronize_rcu run #7: crashed: INFO: task hung in synchronize_rcu run #8: crashed: INFO: task hung in synchronize_rcu run #9: crashed: INFO: task hung in synchronize_rcu run #10: crashed: INFO: task hung in synchronize_rcu run #11: crashed: INFO: task hung in synchronize_rcu run #12: crashed: INFO: task hung in synchronize_rcu run #13: crashed: INFO: task hung in synchronize_rcu run #14: crashed: INFO: task hung in synchronize_rcu run #15: crashed: INFO: task hung in synchronize_rcu run #16: crashed: INFO: task hung in synchronize_rcu run #17: crashed: INFO: task hung in synchronize_rcu run #18: crashed: INFO: task hung in synchronize_rcu run #19: OK testing current HEAD 9be9ed2612b5aedb52a2c240edb1630b6b743cb6 testing commit 9be9ed2612b5aedb52a2c240edb1630b6b743cb6 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: ed4eebaa6605b34751fb2e982337e2e61663798f21618edd2bafa40d998861b8 all runs: OK # git bisect start 9be9ed2612b5aedb52a2c240edb1630b6b743cb6 ea4424be16887a37735d6550cfd0611528dbe5d9 Bisecting: 8125 revisions left to test after this (roughly 13 steps) [25fd2d41b505d0640bdfe67aa77c549de2d3c18a] selftests: kselftest framework: provide "finished" helper testing commit 25fd2d41b505d0640bdfe67aa77c549de2d3c18a compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: dd5829f7ad5ed879e48bf69c2b7a56a19cdec55aa7efef85ab6a89a83bd9ba62 run #0: crashed: SYZFAIL: wrong response packet run #1: crashed: INFO: task hung in synchronize_rcu run #2: crashed: INFO: task hung in synchronize_rcu run #3: crashed: INFO: task hung in synchronize_rcu run #4: crashed: INFO: task hung in synchronize_rcu run #5: crashed: INFO: task hung in synchronize_rcu run #6: OK run #7: OK run #8: OK run #9: OK # git bisect good 25fd2d41b505d0640bdfe67aa77c549de2d3c18a Bisecting: 4230 revisions left to test after this (roughly 12 steps) [ff61bc81b3feebcef4d0431a92e2e40e8d4fe8b3] Merge tag 'pinctrl-v5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl testing commit ff61bc81b3feebcef4d0431a92e2e40e8d4fe8b3 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 48ce7352d9a0c60f5ea75c2b9ba71d6a7071e68fa010e00d7ae724d1e56638c0 run #0: crashed: SYZFAIL: wrong response packet run #1: crashed: general protection fault in kvm_mmu_uninit_tdp_mmu run #2: crashed: INFO: task hung in synchronize_rcu run #3: crashed: INFO: task hung in synchronize_rcu run #4: crashed: INFO: task hung in synchronize_rcu run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK # git bisect good ff61bc81b3feebcef4d0431a92e2e40e8d4fe8b3 Bisecting: 2101 revisions left to test after this (roughly 11 steps) [6a34fdcca452457a530980be2561dab06da3627f] Merge tag 'rtc-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux testing commit 6a34fdcca452457a530980be2561dab06da3627f compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 121c4d8ba2b4c2f6fff7719b6efe02b1223618f054faf234a69597bdd589ed00 run #0: crashed: INFO: task hung in synchronize_rcu run #1: crashed: INFO: task hung in synchronize_rcu run #2: crashed: INFO: task hung in synchronize_rcu run #3: crashed: INFO: task hung in synchronize_rcu run #4: crashed: INFO: task hung in synchronize_rcu run #5: crashed: INFO: task hung in synchronize_rcu run #6: OK run #7: OK run #8: OK run #9: OK # git bisect good 6a34fdcca452457a530980be2561dab06da3627f Bisecting: 1051 revisions left to test after this (roughly 10 steps) [fb649bda6f5642f173ee3429a965c769554f23d8] Merge tag 'block-5.18-2022-04-15' of git://git.kernel.dk/linux-block testing commit fb649bda6f5642f173ee3429a965c769554f23d8 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: b5590d058cc74cbca30501f0412f510d395e4be0d2dfe5487402389aaf1e4cfd all runs: crashed: INFO: task hung in synchronize_rcu # git bisect good fb649bda6f5642f173ee3429a965c769554f23d8 Bisecting: 501 revisions left to test after this (roughly 9 steps) [249aca0d3d631660aa3583c6a3559b75b6e971b4] Merge tag 'net-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net testing commit 249aca0d3d631660aa3583c6a3559b75b6e971b4 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 29a1bb3920d78bd37fcd976435a6ace11517d0641bf013fb4326e6018b2aa103 all runs: OK # git bisect bad 249aca0d3d631660aa3583c6a3559b75b6e971b4 Bisecting: 276 revisions left to test after this (roughly 8 steps) [7200095feadfb9792b744a5a6e20249ce77bc6d7] Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux testing commit 7200095feadfb9792b744a5a6e20249ce77bc6d7 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 3e86cb831b4ca809d110acae40fd7afc629244bf3cffc47df04a1f48f33d7aec run #0: crashed: SYZFAIL: wrong response packet run #1: crashed: INFO: task hung in synchronize_rcu run #2: crashed: INFO: task hung in synchronize_rcu run #3: crashed: INFO: task hung in synchronize_rcu run #4: crashed: INFO: task hung in synchronize_rcu run #5: crashed: INFO: task hung in synchronize_rcu run #6: crashed: INFO: task hung in synchronize_rcu run #7: crashed: INFO: task hung in synchronize_rcu run #8: crashed: INFO: task hung in synchronize_rcu run #9: crashed: INFO: task hung in synchronize_rcu # git bisect good 7200095feadfb9792b744a5a6e20249ce77bc6d7 Bisecting: 140 revisions left to test after this (roughly 7 steps) [cf424ef014ac30b0da27125dd1fbdf10b0d3a520] Merge tag 'for-5.18/fbdev-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev testing commit cf424ef014ac30b0da27125dd1fbdf10b0d3a520 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 513cd5073b09919b983708adeb719f24ed149328b3c6ca885db7fcde10360415 all runs: OK # git bisect bad cf424ef014ac30b0da27125dd1fbdf10b0d3a520 Bisecting: 68 revisions left to test after this (roughly 6 steps) [13bc32bad7059d6c5671e9d037e6e3ed001cc0f4] Merge tag 'drm-fixes-2022-04-23' of git://anongit.freedesktop.org/drm/drm testing commit 13bc32bad7059d6c5671e9d037e6e3ed001cc0f4 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 081929be3de5a23d65b5c302a5e8e822d626e4089f634f7cce87b109652ca9a9 all runs: OK # git bisect bad 13bc32bad7059d6c5671e9d037e6e3ed001cc0f4 Bisecting: 38 revisions left to test after this (roughly 5 steps) [2e5991fa39e4eec45eb37a680bfdff18129cefd9] Merge tag 'ata-5.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata testing commit 2e5991fa39e4eec45eb37a680bfdff18129cefd9 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: c521caaef0e47e24be96a5093a90cc64b3d23867450b29b3716b44128c6344e3 run #0: basic kernel testing failed: BUG: program execution failed: executor NUM: EOF 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 # git bisect bad 2e5991fa39e4eec45eb37a680bfdff18129cefd9 Bisecting: 13 revisions left to test after this (roughly 4 steps) [75189d1de1b377e580ebd2d2c55914631eac9c64] KVM: x86/pmu: Update AMD PMC sample period to fix guest NMI-watchdog testing commit 75189d1de1b377e580ebd2d2c55914631eac9c64 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 08cae15df9967d7084636fec98a875fd66ef33613fb5b3b0828ea254b823c48a run #0: basic kernel testing failed: BUG: program execution failed: executor NUM: EOF 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 # git bisect bad 75189d1de1b377e580ebd2d2c55914631eac9c64 Bisecting: 6 revisions left to test after this (roughly 3 steps) [5c697c367a66307a5d943c3449421aff2aa3ca4a] KVM: Initialize debugfs_dentry when a VM is created to avoid NULL deref testing commit 5c697c367a66307a5d943c3449421aff2aa3ca4a compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 62c8f317eaa3804abf0de675ef3a17ccefc60002c7db36fc66912c6ea65ad8d8 all runs: OK # git bisect bad 5c697c367a66307a5d943c3449421aff2aa3ca4a Bisecting: 3 revisions left to test after this (roughly 2 steps) [012c722569f171d58169606908ebbb8713f1609e] Merge tag 'kvm-riscv-fixes-5.18-2' of https://github.com/kvm-riscv/linux into HEAD testing commit 012c722569f171d58169606908ebbb8713f1609e compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: bc0fa87ae2d1fd0edeccff23592582ca03fa9e0bf30481ace773b341b3339fb5 run #0: basic kernel testing failed: BUG: program execution failed: executor NUM: EOF run #1: crashed: INFO: task hung in synchronize_rcu run #2: crashed: INFO: task hung in synchronize_rcu run #3: crashed: INFO: task hung in synchronize_rcu run #4: crashed: INFO: task hung in synchronize_rcu run #5: crashed: INFO: task hung in synchronize_rcu run #6: crashed: INFO: task hung in synchronize_rcu run #7: crashed: INFO: task hung in synchronize_rcu run #8: crashed: INFO: task hung in synchronize_rcu run #9: crashed: INFO: task hung in synchronize_rcu # git bisect good 012c722569f171d58169606908ebbb8713f1609e Bisecting: 1 revision left to test after this (roughly 1 step) [fdd6f6ac2e489b9b256cd05a880d13bfdbac7c2e] KVM: RISC-V: Use kvm_vcpu.srcu_idx, drop RISC-V's unnecessary copy testing commit fdd6f6ac2e489b9b256cd05a880d13bfdbac7c2e compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 45638849543b516014b018dfea36f2336d54c6463adace8b50b9dfba0510b879 all runs: OK # git bisect bad fdd6f6ac2e489b9b256cd05a880d13bfdbac7c2e Bisecting: 0 revisions left to test after this (roughly 0 steps) [2d08935682ac5f6bfb70f7e6844ec27d4a245fa4] KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() testing commit 2d08935682ac5f6bfb70f7e6844ec27d4a245fa4 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: dc99b024af85ea75abc632c9896937ab01a5a86558059312689b48f8164fbbce all runs: OK # git bisect bad 2d08935682ac5f6bfb70f7e6844ec27d4a245fa4 2d08935682ac5f6bfb70f7e6844ec27d4a245fa4 is the first bad commit commit 2d08935682ac5f6bfb70f7e6844ec27d4a245fa4 Author: Sean Christopherson Date: Fri Apr 15 00:43:41 2022 +0000 KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() Don't re-acquire SRCU in complete_emulated_io() now that KVM acquires the lock in kvm_arch_vcpu_ioctl_run(). More importantly, don't overwrite vcpu->srcu_idx. If the index acquired by complete_emulated_io() differs from the one acquired by kvm_arch_vcpu_ioctl_run(), KVM will effectively leak a lock and hang if/when synchronize_srcu() is invoked for the relevant grace period. Fixes: 8d25b7beca7e ("KVM: x86: pull kvm->srcu read-side to kvm_arch_vcpu_ioctl_run") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky Message-Id: <20220415004343.2203171-2-seanjc@google.com> Signed-off-by: Paolo Bonzini arch/x86/kvm/x86.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) culprit signature: dc99b024af85ea75abc632c9896937ab01a5a86558059312689b48f8164fbbce parent signature: bc0fa87ae2d1fd0edeccff23592582ca03fa9e0bf30481ace773b341b3339fb5 revisions tested: 16, total time: 4h25m43.794861435s (build: 1h37m22.551762205s, test: 2h46m57.337330219s) first good commit: 2d08935682ac5f6bfb70f7e6844ec27d4a245fa4 KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() recipients (to): ["mlevitsk@redhat.com" "pbonzini@redhat.com" "seanjc@google.com"] recipients (cc): []