On Sat 2018-02-24 13:34:05, kernel test robot wrote: > TO: Petr Mladek <[email protected]> > CC: Cong Wang <[email protected]>, Dave Hansen > <[email protected]>, Johannes Weiner <[email protected]>, Mel Gorman > <[email protected]>, Michal Hocko <[email protected]>, Vlastimil Babka > <[email protected]>, Peter Zijlstra <[email protected]>, Linus Torvalds > <[email protected]>, Jan Kara <[email protected]>, Mathieu Desnoyers > <[email protected]>, Tetsuo Handa > <[email protected]>, Byungchul Park > <[email protected]>, Tejun Heo <[email protected]>, Pavel Machek > <[email protected]>, Steven Rostedt (VMware) <[email protected]>, Sergey > Senozhatsky <[email protected]>, LKML > <[email protected]>, [email protected], [email protected] > > > > FYI, we noticed the following commit (built with gcc-7): > > commit: c162d5b4338d72deed61aa65ed0f2f4ba2bbc8ab ("printk: Hide console > waiter logic into helpers") > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > in testcase: boot > > on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 1G > > caused below changes (please refer to attached dmesg/kmsg for entire > log/backtrace): > > > +--------------------------------+------------+------------+ > | | dbdda842fe | c162d5b433 | > +--------------------------------+------------+------------+ > | boot_successes | 0 | 0 | > | boot_failures | 18 | 16 | > | BUG:KASAN:use-after-scope_in_p | 18 | | > | BUG:KASAN:use-after-scope_in_c | 0 | 16 | > +--------------------------------+------------+------------+ > > > > [ 0.003333] BUG: KASAN: use-after-scope in console_unlock+0x185/0x960 > [ 0.003333] BUG: KASAN: use-after-scope in console_unlock+0x185/0x960
Is there any change to get disassembly of console_unlock() from the problematic build? I have troubles to reproduce this myself. Also I was not able to find any bug just by looking into the code yet. The disassembly might help a lot here. Interesting symptoms (for myself and other debuggers): The lines are duplicated. Therefore it happened when real console was registered and before the early console was unregistered. See also the full dmesg for these actions. The related printk messages are right after the KASAN report. I wonder if it is unsafe to pass the console_lock via console_trylock_spinnning() from console_unlock() called in register_console(). I do not see any problem but I might be blind. Another interesting thing is that the entire KASAN report is duplicated. I wonder if it is a two level duplication or if the BUG() was really triggered twice. > To reproduce: > > git clone https://github.com/intel/lkp-tests.git > cd lkp-tests > bin/lkp qemu -k <bzImage> job-script # job-script is attached in > this email Also the job-script was not attached. Is it because the problem happened already during the boot? Thanks for the report. Best Regards, Petr
