On Sun, Jun 19, 2022 at 08:58:22PM +0200, Jonathan Cameron wrote: > Vincent: I'm getting some instability with roadtest after forwards porting to > current mainline. Tests run 'sometimes'. Other times I get a crash > in um_set_signal. Seems unrelated to the test this series adds. My local work-in-progress version has a lot of changes since the RFC, but yes, I'm seeing a splat too (below) if I use the RFC version on v5.19-rc3. The problem goes away if I enable CONFIG_UML_RANDOM=y, as I have done in my local branch: diff --git a/tools/testing/roadtest/roadtest/tests/base/config b/tools/testing/roadtest/roadtest/tests/base/config index c1952d047c8e..74b201c48d42 100644 --- a/tools/testing/roadtest/roadtest/tests/base/config +++ b/tools/testing/roadtest/roadtest/tests/base/config @@ -4,6 +4,7 @@ CONFIG_LOG_BUF_SHIFT=14 CONFIG_EXPERT=y CONFIG_HOSTFS=y CONFIG_UML_TIME_TRAVEL_SUPPORT=y +CONFIG_UML_RANDOM=y CONFIG_NULL_CHAN=y CONFIG_PORT_CHAN=y CONFIG_PTY_CHAN=y [ 547.130000][ T21] BUG: failure at arch/um/kernel/time.c:415/time_travel_update_time()! [ 547.130000][ T21] Kernel panic - not syncing: BUG! [ 547.130000][ T21] CPU: 0 PID: 21 Comm: python3 Not tainted 5.19.0-rc3-00018-gcb2e63986f7f #77 [ 547.130000][ T21] Stack: [ 547.130000][ T21] 605860dd 60290b07 60037130 00000000 [ 547.130000][ T21] 605860dd 00000000 607a39d0 60426253 [ 547.130000][ T21] 6064d1a8 00000000 604106ad 60557d16 [ 547.130000][ T21] Call Trace: [ 547.130000][ T21] [<60290b07>] ? dump_stack_print_info+0xd7/0xf0 [ 547.130000][ T21] [<60037130>] ? um_set_signals+0x0/0x50 [ 547.130000][ T21] [<60426253>] ? dump_stack_lvl+0x5b/0x7a [ 547.130000][ T21] [<604106ad>] ? _printk+0x0/0x9b [ 547.130000][ T21] [<60025440>] ? time_travel_del_event+0x0/0xc0 [ 547.130000][ T21] [<6040b016>] ? panic+0x1a8/0x372 [ 547.130000][ T21] [<6040ae6e>] ? panic+0x0/0x372 [ 547.130000][ T21] [<604106ad>] ? _printk+0x0/0x9b [ 547.130000][ T21] [<60037130>] ? um_set_signals+0x0/0x50 [ 547.130000][ T21] [<60037174>] ? um_set_signals+0x44/0x50 [ 547.130000][ T21] [<60025440>] ? time_travel_del_event+0x0/0xc0 [ 547.130000][ T21] [<60409c35>] ? time_travel_update_time.cold+0x6c/0x133 [ 547.130000][ T21] [<6043b5f0>] ? __schedule+0x780/0x880 [ 547.130000][ T21] [<6043ae70>] ? __schedule+0x0/0x880 [ 547.130000][ T21] [<600bd220>] ? random_get_entropy_fallback+0x0/0x30 [ 547.130000][ T21] [<6003be10>] ? get_fp_registers+0x0/0x80 [ 547.130000][ T21] [<600258fd>] ? timer_read+0xbd/0xf0 [ 547.130000][ T21] [<60305fb0>] ? mix_pool_bytes+0x0/0x60 [ 547.130000][ T21] [<60305fb0>] ? mix_pool_bytes+0x0/0x60 [ 547.130000][ T21] [<60430d32>] ? try_to_generate_entropy+0x14d/0x164 [ 547.130000][ T21] [<60430f98>] ? entropy_timer+0x0/0x48 [ 547.130000][ T21] [<60431049>] ? urandom_read_iter.cold+0xc/0x11 [ 547.130000][ T21] [<60176b52>] ? new_sync_read+0xe2/0x150 [ 547.130000][ T21] [<60178dc2>] ? vfs_read+0xf2/0x200 [ 547.130000][ T21] [<601a51d5>] ? __fdget_pos+0x15/0x60 [ 547.130000][ T21] [<601793a1>] ? ksys_read+0x61/0xf0 [ 547.130000][ T21] [<600280ca>] ? handle_syscall+0xaa/0xf0 [ 547.130000][ T21] [<60039236>] ? userspace+0x346/0x570 [ 547.130000][ T21] [<60037130>] ? um_set_signals+0x0/0x50
