At 11:35 08/10/08, Nick Piggin wrote: >On Wednesday 08 October 2008 05:59, Peter Zijlstra wrote: >> >> The whole point is that such usage is outside the specification and thus >> we don't strictly need to fix this. >> >> So the question Nick is asking is, do we want to slow down the kernel >> for a few broken user-space applications. Esp. since the race doesn't >> affect anybody else except the broken users of the file descriptor. > >Right you are. That's the fundamental question. The actual details of >the fix and how likely the race is don't really matter until we >answer the first question (except to say that the "fix" is never going >to be free). Simultaneous access by two or more writer can corrupt file content, so this case needs some locks(flock or fcntl) to preserve synchronization of file content. This is responsibility of user-space application. But file->f_pos race issue can occur even if multiple threads just read simultaneously. I think this is not responsibility of user-space application. To avoid this currently, an application needs some locks to protect file offset even if it just read a file. So I think f_pos race should be fixed. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
