Messages in this thread | | | Date | Tue, 15 Dec 2015 19:16:29 +0100 | From | Oleg Nesterov <> | Subject | Re: [tip:locking/core] sched/wait: Fix signal handling in bit wait helpers |
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On 12/11, Peter Zijlstra wrote: > > On Fri, Dec 11, 2015 at 03:30:33AM -0800, Paul Turner wrote: > > > > Blergh, all I've managed to far is to confuse myself further. Even > > > something like the original (+- the EINTR) should work when we consider > > > the looping, even when mixed with an occasional spurious wakeup. > > > > > > > > > int bit_wait() > > > { > > > if (signal_pending_state(current->state, current)) > > > return -EINTR; > > > schedule(); > > > } > > So I asked Vladimir to test that (simply changing the return from 1 to > -EINTR) and it made his fail much less likely but it still failed in the > same way. > > So I'm fairly sure I'm still missing something :/
Same here...
Yes, "return 1" in bit_wait_io() doesn't look right. For example do_generic_file_read() can wrongly return if lock_page_killable() returns this error code. But I fail to understand how this can read to rcu-stall.
Oleg.
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