Two more small fixes

 - The conversion of enums into their actual numbers to display
   in the event format file had an off-by-one bug, that could cause
   an enum not to be converted, and break user space parsing tools.

 - A fix to a previous fix to bring back the context recursion checks.
   The interrupt case checks for NMI, IRQ and softirq, but the softirq
   returned the same number regardless if it was set or not, although
   the logic would force it to be set if it were hit.
-----BEGIN PGP SIGNATURE-----
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=O7m4
-----END PGP SIGNATURE-----
tracing: Fix converting enum's from the map in trace_event_eval_update()

Since enums do not get converted by the TRACE_EVENT macro into their values,
the event format displaces the enum name and not the value. This breaks
tools like perf and trace-cmd that need to interpret the raw binary data. To
solve this, an enum map was created to convert these enums into their actual
numbers on boot up. This is done by TRACE_EVENTS() adding a
TRACE_DEFINE_ENUM() macro.

Some enums were not being converted. This was caused by an optization that
had a bug in it.

All calls get checked against this enum map to see if it should be converted
or not, and it compares the call's system to the system that the enum map
was created under. If they match, then they call is processed.

To cut down on the number of iterations needed to find the maps with a
matching system, since calls and maps are grouped by system, when a match is
made, the index into the map array is saved, so that the next call, if it
belongs to the same system as the previous call, could start right at that
array index and not have to scan all the previous arrays.

The problem was, the saved index was used as the variable to know if this is
a call in a new system or not. If the index was zero, it was assumed that
the call is in a new system and would keep incrementing the saved index
until it found a matching system. The issue arises when the first matching
system was at index zero. The next map, if it belonged to the same system,
would then think it was the first match and increment the index to one. If
the next call belong to the same system, it would begin its search of the
maps off by one, and miss the first enum that should be converted. This left
a single enum not converted properly.

Also add a comment to describe exactly what that index was for. It took me a
bit too long to figure out what I was thinking when debugging this issue.

Link: http://lkml.kernel.org/r/717BE572-2070-4C1E-9902-9F2E0FEDA4F8@oracle.com

Cc: stable@vger.kernel.org
Fixes: 0c564a538aa93 ("tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values")
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Teste-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
1 file changed