path: root/ipc
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authorTejun Heo <>2005-08-05 13:28:11 -0700
committerLinus Torvalds <>2005-08-05 13:43:16 -0700
commitba02508248e90a9d696aebd18b48a3290235b53c (patch)
tree4167aecae57a5ceab6392e54189a271f3dfdebf8 /ipc
parentc7546f8f03f5a4fa612605b6be930234d6026860 (diff)
[PATCH] blk: fix tag shrinking (revive real_max_size)
My patch in commit fa72b903f75e4f0f0b2c2feed093005167da4023 incorrectly removed blk_queue_tag->real_max_depth. The original resize implementation was incorrect in the following points. * actual allocation size of tag_index was shorter than real_max_size, but assumed to be of the same size, possibly causing memory access beyond the allocated area. * bits in tag_map between max_deptn and real_max_depth were initialized to 1's, making the tags permanently reserved. In an attempt to fix above two bugs, I had removed allocation optimization in init_tag_map and real_max_size. Tag map/index were allocated and freed immediately during resize. Unfortunately, I wasn't considering that tag map/index can be resized dynamically with tags beyond new_depth active. This led to accessing freed area after shrinking tags and led to the following bug reporting thread on linux-scsi. To fix the problem, I've revived real_max_depth without allocation optimization in init_tag_map, and Andrew Vasquez confirmed that the problem was fixed. As Jens is not going to be available for a week, he asked me to make sure that this patch reaches you. Also, a comment was added to make sure that real_max_size is needed for dynamic shrinking. Signed-off-by: Tejun Heo <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
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