Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 19 Mar 2019 14:35:07 +0100 | Subject | Re: [syzbot? printk?] no WARN_ON() messages printed before "Kernel panic - not syncing: panic_on_warn set ..." |
| |
On Tue, Mar 19, 2019 at 1:35 PM Sergey Senozhatsky <sergey.senozhatsky@gmail.com> wrote: > > On (03/19/19 09:10), Dmitry Vyukov wrote: > > [..] > > > In some setups we read out output with "dmesg -w" (should stream > > output as well) in absence of a better solution. Will this be affected > > by SYSLOG_ACTION_CLEAR? > > There is a small chance that syslog/devkmsg can be affected > > syslog_clear() > { > clear_seq = log_next_seq; > clear_idx = log_next_idx; > } > > syslog_print_all() > { > ... > seq = clear_seq; > idx = clear_idx; > while (seq < log_next_seq) { > ... > len += msg_print_text(msg, true, time, NULL, 0); > } > ... > } > > devkmsg also may be affected > > syslog_clear() > { > clear_seq = log_next_seq; > clear_idx = log_next_idx; > } > > devkmsg_llseek() > { > ... > case SEEK_DATA: > user->idx = clear_idx; > user->seq = clear_seq; > break; > ... > } > > user->idx/user->seq then are used in devkmsg poll()/read(). syslog is > more likely to be affected, I think.
SYSLOG_ACTION_CLEAR is disabled: https://github.com/google/syzkaller/commit/28c04d39e052ee2960eebc16a3f7fba88920cd52
| |