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net: sched: cls_u32: Fix match key mis-addressing
[ Upstream commit e68409db995380d1badacba41ff24996bd396171 ] A match entry is uniquely identified with an "address" or "path" in the form of: hashtable ID(12b):bucketid(8b):nodeid(12b). When creating table match entries all of hash table id, bucket id and node (match entry id) are needed to be either specified by the user or reasonable in-kernel defaults are used. The in-kernel default for a table id is 0x800(omnipresent root table); for bucketid it is 0x0. Prior to this fix there was none for a nodeid i.e. the code assumed that the user passed the correct nodeid and if the user passes a nodeid of 0 (as Mingi Cho did) then that is what was used. But nodeid of 0 is reserved for identifying the table. This is not a problem until we dump. The dump code notices that the nodeid is zero and assumes it is referencing a table and therefore references table struct tc_u_hnode instead of what was created i.e match entry struct tc_u_knode. Ming does an equivalent of: tc filter add dev dummy0 parent 10: prio 1 handle 0x1000 \ protocol ip u32 match ip src 10.0.0.1/32 classid 10:1 action ok Essentially specifying a table id 0, bucketid 1 and nodeid of zero Tableid 0 is remapped to the default of 0x800. Bucketid 1 is ignored and defaults to 0x00. Nodeid was assumed to be what Ming passed - 0x000 dumping before fix shows: ~$ tc filter ls dev dummy0 parent 10: filter protocol ip pref 1 u32 chain 0 filter protocol ip pref 1 u32 chain 0 fh 800: ht divisor 1 filter protocol ip pref 1 u32 chain 0 fh 800: ht divisor -30591 Note that the last line reports a table instead of a match entry (you can tell this because it says "ht divisor..."). As a result of reporting the wrong data type (misinterpretting of struct tc_u_knode as being struct tc_u_hnode) the divisor is reported with value of -30591. Ming identified this as part of the heap address (physmap_base is 0xffff8880 (-30591 - 1)). The fix is to ensure that when table entry matches are added and no nodeid is specified (i.e nodeid == 0) then we get the next available nodeid from the table's pool. After the fix, this is what the dump shows: $ tc filter ls dev dummy0 parent 10: filter protocol ip pref 1 u32 chain 0 filter protocol ip pref 1 u32 chain 0 fh 800: ht divisor 1 filter protocol ip pref 1 u32 chain 0 fh 800::800 order 2048 key ht 800 bkt 0 flowid 10:1 not_in_hw match 0a000001/ffffffff at 12 action order 1: gact action pass random type none pass val 0 index 1 ref 1 bind 1 Reported-by:Mingi Cho <mgcho.minic@gmail.com> Fixes: 1da177e4 ("Linux-2.6.12-rc2") Signed-off-by: