Messages in this thread | | | Subject | Re: [patch 2.4] make tty->count atomic_t | From | Jes Sorensen <> | Date | 03 Apr 2003 18:18:22 -0500 |
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>>>>> "Russell" == Russell King <rmk@arm.linux.org.uk> writes:
Russell> On Thu, Apr 03, 2003 at 12:16:21PM -0500, Jes Sorensen wrote: >> I believe the 2.4 tty code is racey in the way it handles >> tty->count. release_dev() does the tty->count-- thing without >> protecting against parallel execution, hence tty->count can end up >> a random state as tty-> count-- isn't guaranteed to be atomic (load-store architectures tty-> and >> architectures with weak memory ordering etc).
Russell> Isn't release_dev() only called under the BKL, which Russell> guarantees the old "single-thread in the kernel at a time" Russell> behaviour from pre-SMP Linux ?
It's called from tty_release() and tty_open(). tty_release() grabs the BKL but I don't see the path that grabs it when calling through tty_open() (doesn't mean I am not blind of course ;-).
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