On Wed, May 06, 2015 at 08:44:29AM -0700, Josh Triplett wrote: > On Wed, May 06, 2015 at 05:08:50PM +0800, Fengguang Wu wrote: > > FYI, the reported bug is still not fixed in linux-next 20150506. > > This isn't the same bug. The previous one you mentioned was a userspace > assertion failure in libnih, likely caused because some part of upstart > didn't have appropriate error handling for some syscall returning > ENOSYS; that one wasn't an issue, since CONFIG_MULTIUSER=n is not > expected to boot a standard Linux distribution. > > This one, on the other hand, is a kernel panic, and does need fixing. > > > commit 2813893f8b197a14f1e1ddb04d99bce46817c84a > > > > +-----------------------------------------------------------+------------+------------+------------+ > > | | c79574abe2 | 2813893f8b | cbdacaf0c1 | > > +-----------------------------------------------------------+------------+------------+------------+ > > | boot_successes | 60 | 0 | 0 | > > | boot_failures | 0 | 22 | 1064 | > > | BUG:unable_to_handle_kernel | 0 | 22 | 1032 | > > | Oops | 0 | 22 | 1032 | > > | EIP_is_at_devpts_new_index | 0 | 22 | 1032 | > > | Kernel_panic-not_syncing:Fatal_exception | 0 | 22 | 1032 | > > | backtrace:do_sys_open | 0 | 22 | 1032 | > > | backtrace:SyS_open | 0 | 22 | 1032 | > > | WARNING:at_arch/x86/kernel/fpu/core.c:#fpu__clear() | 0 | 0 | 32 | > > | Kernel_panic-not_syncing:Attempted_to_kill_init!exitcode= | 0 | 0 | 32 | > > +-----------------------------------------------------------+------------+------------+------------+ > > Is this table saying the number of times the type of error in the first > column occurred in each commit? > > In any case, investigating. Iulia, can you look at this as well? > > I'm digging through the call stack, and I'm having a hard time seeing > how the CONFIG_MULTIUSER patch could affect anything here. Update: it looks like init_devpts_fs is getting ERR_PTR(-EINVAL) back from kern_mount and storing that in devpts_mnt; later, devpts_new_index pokes at devpts_mnt and explodes. So, there are two separate bugs here. On the one hand, CONFIG_MULTIUSER should not be causing kern_mount to fail with -EINVAL; tracking that down now. On the other hand, devpts and ptmx should handle the failure better, without crashing; ptmx_open should have gracefully failed back to userspace with -ENODEV or something, since ptmx doesn't make sense without devpts. I'll send a patch for that too. - Josh Triplett -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>