bisecting fixing commit since 9a95f25269bd9257ab9fba7bb14355d50b5f39ec
building syzkaller on c8e81ce4c7e3b59e7c83c6fab56c217916f3b3b6
testing commit 9a95f25269bd9257ab9fba7bb14355d50b5f39ec
compiler: gcc version 8.4.1 20210217 (GCC)
kernel signature: 2d0a4208e95d20d53d0a015ea43ff8dead06dc008167785de6c797e4dff7188f
run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #1: crashed: BUG: unable to handle kernel
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #4: crashed: BUG: unable to handle kernel
run #5: crashed: BUG: unable to handle kernel
run #6: crashed: BUG: unable to handle kernel
run #7: crashed: BUG: unable to handle kernel
run #8: crashed: BUG: unable to handle kernel
run #9: crashed: BUG: unable to handle kernel
run #10: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #11: crashed: BUG: unable to handle kernel
run #12: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #13: crashed: BUG: unable to handle kernel
run #14: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #15: crashed: BUG: unable to handle kernel
run #16: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #17: crashed: BUG: unable to handle kernel NULL pointer dereference in blk_mq_map_swqueue
run #18: crashed: BUG: unable to handle kernel
run #19: crashed: BUG: unable to handle kernel
testing current HEAD 8ea4f73cfa7e0555dc03aedde52db54a6587ab43
testing commit 8ea4f73cfa7e0555dc03aedde52db54a6587ab43
compiler: gcc version 8.4.1 20210217 (GCC)
kernel signature: 46ccf10a58027fc33b7709f2629bcd6014dbdb32dd56d6a722adec2d835eadcb
all runs: crashed: unregister_netdevice: waiting for DEV to become free
revisions tested: 2, total time: 28m7.10747159s (build: 20m35.13614769s, test: 6m35.597214128s)
the crash still happens on HEAD
commit msg: Linux 4.14.247
crash: unregister_netdevice: waiting for DEV to become free
unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1