On Sat, May 07, 2016 at 08:55:56PM +0000, Abhishek Kulkarni wrote: > Hello All, > > I was using Dtrace using the FBT provider on an arm platform with witness > enabled. When FBT is used with the kernel module, it generates a kernel panic > or the system becomes unresponsive. Is this problem know or seen before. I am > copying the kernel backtrace below for reference. The issue seems to be with > a blockable sleep lock(kld_sx) acquired which is conflicting with the > td->td_critnest positive value.
Unfortunately, I think this is expected. The ARM port of DTrace will call into the kernel linker from probe context to perform stack unwinding. This is a bug since the kernel linker cannot be entered in arbitrary contexts - the thread might already hold the linker lock, or might hold a critical section as in your example. This is a known issue, but I'm not sure if anyone is working on fixing it. -Mark _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-dtrace To unsubscribe, send any mail to "[email protected]"
