bisecting fixing commit since 9791581c049c10929e97098374dd1716a81fefcc
building syzkaller on d4f4eca56fbea6f58a4d5adfd19cb5e0dc32fe46
testing commit 9791581c049c10929e97098374dd1716a81fefcc with gcc (GCC) 10.2.1 20210217
kernel signature: 399b3e26da0329912b73f554dd90a6566e52f5f5e8b5e927a1fab5a8f616d72c
run #0: crashed: UBSAN: array-index-out-of-bounds in decode_data
run #1: crashed: UBSAN: array-index-out-of-bounds in decode_data
run #2: crashed: UBSAN: array-index-out-of-bounds in decode_data
run #3: crashed: UBSAN: array-index-out-of-bounds in decode_data
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
reproducer seems to be flaky
testing current HEAD f296bfd5cd04cbb49b8fc9585adc280ab2b58624
testing commit f296bfd5cd04cbb49b8fc9585adc280ab2b58624 with gcc (GCC) 10.2.1 20210217
kernel signature: 894e191c3f4d346e5ed85d3b6fe4c9d5c0e664cf048389450f377a1bb0fc9ac4
run #0: crashed: UBSAN: array-index-out-of-bounds in decode_data
run #1: crashed: UBSAN: array-index-out-of-bounds in decode_data
run #2: crashed: UBSAN: array-index-out-of-bounds in decode_data
run #3: crashed: UBSAN: array-index-out-of-bounds in decode_data
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
Reproducer flagged being flaky
revisions tested: 2, total time: 29m37.997474269s (build: 10m48.04798091s, test: 18m21.857678969s)
the crash still happens on HEAD
commit msg: Merge tag 'nfs-for-5.12-2' of git://git.linux-nfs.org/projects/anna/linux-nfs
crash: UBSAN: array-index-out-of-bounds in decode_data
================================================================================
UBSAN: array-index-out-of-bounds in drivers/net/hamradio/6pack.c:840:16
index 400 is out of range for type 'unsigned char [400]'
CPU: 1 PID: 153 Comm: kworker/u4:3 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x93/0xc2 lib/dump_stack.c:120
 ubsan_epilogue+0x5/0x40 lib/ubsan.c:148
 __ubsan_handle_out_of_bounds.cold+0x43/0x48 lib/ubsan.c:288
 decode_data.part.0+0x2c7/0x2d0 drivers/net/hamradio/6pack.c:840
 decode_data drivers/net/hamradio/6pack.c:960 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:963 [inline]
 sixpack_receive_buf drivers/net/hamradio/6pack.c:453 [inline]
 sixpack_receive_buf+0xaef/0x10c0 drivers/net/hamradio/6pack.c:430
 tty_ldisc_receive_buf+0xf5/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x5c/0x90 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x19c/0x3d0 drivers/tty/tty_buffer.c:533
 process_one_work+0x84c/0x13b0 kernel/workqueue.c:2275
 worker_thread+0x598/0xf80 kernel/workqueue.c:2421
 kthread+0x36f/0x450 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
================================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 153 Comm: kworker/u4:3 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x93/0xc2 lib/dump_stack.c:120
 panic+0x256/0x4eb kernel/panic.c:231
 ubsan_epilogue+0x3f/0x40 lib/ubsan.c:162
 __ubsan_handle_out_of_bounds.cold+0x43/0x48 lib/ubsan.c:288
 decode_data.part.0+0x2c7/0x2d0 drivers/net/hamradio/6pack.c:840
 decode_data drivers/net/hamradio/6pack.c:960 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:963 [inline]
 sixpack_receive_buf drivers/net/hamradio/6pack.c:453 [inline]
 sixpack_receive_buf+0xaef/0x10c0 drivers/net/hamradio/6pack.c:430
 tty_ldisc_receive_buf+0xf5/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x5c/0x90 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x19c/0x3d0 drivers/tty/tty_buffer.c:533
 process_one_work+0x84c/0x13b0 kernel/workqueue.c:2275
 worker_thread+0x598/0xf80 kernel/workqueue.c:2421
 kthread+0x36f/0x450 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..