Messages in this thread |  | | Date | Wed, 26 Feb 2014 15:13:22 -0500 | From | Steven Rostedt <> | Subject | Re: [RFC PATCH] Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE |
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On Wed, 26 Feb 2014 13:23:56 +1030 Rusty Russell <rusty@rustcorp.com.au> wrote:
> > The one that I replied to. I can't pull the module patch unless I get > > an ack from Rusty. > > Ah, I applied it in my tree. Happy for you to take it though; here's > the variant with an Acked-by from me instead of Signed-off-by if you > want it: > > === > From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > Subject: Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE > > Users have reported being unable to trace non-signed modules loaded > within a kernel supporting module signature. > > This is caused by tracepoint.c:tracepoint_module_coming() refusing to > take into account tracepoints sitting within force-loaded modules > (TAINT_FORCED_MODULE). The reason for this check, in the first place, is > that a force-loaded module may have a struct module incompatible with > the layout expected by the kernel, and can thus cause a kernel crash > upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y. > > Tracepoints, however, specifically accept TAINT_OOT_MODULE and > TAINT_CRAP, since those modules do not lead to the "very likely system > crash" issue cited above for force-loaded modules. > > With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed > module is tainted re-using the TAINT_FORCED_MODULE taint flag. > Unfortunately, this means that Tracepoints treat that module as a > force-loaded module, and thus silently refuse to consider any tracepoint > within this module. > > Since an unsigned module does not fit within the "very likely system > crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag > to specifically address this taint behavior, and accept those modules > within Tracepoints. This flag is assigned to the letter 'N', since all > the more obvious ones (e.g. 'S') were already taken. > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > Nacked-by: Ingo Molnar <mingo@kernel.org> > CC: Steven Rostedt <rostedt@goodmis.org> > CC: Thomas Gleixner <tglx@linutronix.de> > CC: David Howells <dhowells@redhat.com> > CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Acked-by: Rusty Russell <rusty@rustcorp.com.au>
There's another version of this as Mathieu pointed out. You can take it. I hate to be the committer of a patch with Ingo's Nack ;-)
-- Steve
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