Messages in this thread | | | Date | Fri, 10 May 2013 13:46:06 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 7/9] liblockdep: Support using LD_PRELOAD |
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On Fri, May 10, 2013 at 01:17:19PM +0200, Peter Zijlstra wrote: > On Thu, May 09, 2013 at 11:58:07AM -0400, Sasha Levin wrote: > > + /* > > + * Some programs attempt to initialize and use locks in their > > + * allocation path. This means that a call to malloc() would > > + * result in locks being initialized and locked. > > + * > > + * Why is it an issue for us? dlsym() below will try allocating to > > + * give us the original function. Since this allocation will result > > + * in a locking operations, we have to let pthread deal with it, > > + * but we can't! we don't have the pointer to the original API > > + * since we're inside dlsym() trying to get it :( > > + * > > + * We can work around it by telling the program that locking was > > + * really okay, and just initialize those locks when we're fully > > + * up and running (this is ok because this all happens during > > + * initialization phase, when we have just one thread). But > > + * this is a big TODO at this point. > > + */ > > + if (preload_started) { > > + printf( > > + "LOCKDEP error: It seems that the program you are trying to " > > + "debug is initializing locks in it's allocation path.\n" > > + "This means that liblockdep cannot reliably analyze this " > > + "program since we need the allocator to work before we can " > > + "debug locks.\nSorry!\n"); > > + > > + exit(1); > > + } > > > Would something like the below cure things? Obviously this hasn't been near a > compiler for the entire thing still isn't wanting to compile for me.
OK, that won't do indeed. Not being able to malloc is only part of the problem.
/me goes stare at it more
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