CVE-2023-54171

In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix memory leak of iter->temp when reading trace_pipe

kmemleak reports: unreferenced object 0xffff88814d14e200 (size 256): comm "cat", pid 336, jiffies 4294871818 (age 779.490s) hex dump (first 32 bytes): 04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................ 0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z...... backtrace: [<ffffffff9bdff18f>] __kmalloc+0x4f/0x140 [<ffffffff9bc9238b>] tracefindnextentry+0xbb/0x1d0 [<ffffffff9bc9caef>] traceprintlatcontext+0xaf/0x4e0 [<ffffffff9bc94490>] printtraceline+0x3e0/0x950 [<ffffffff9bc95499>] tracingreadpipe+0x2d9/0x5a0 [<ffffffff9bf03a43>] vfsread+0x143/0x520 [<ffffffff9bf04c2d>] ksysread+0xbd/0x160 [<ffffffff9d0f0edf>] dosyscall64+0x3f/0x90 [<ffffffff9d2000aa>] entrySYSCALL64afterhwframe+0x6e/0xd8

when reading file 'tracepipe', 'iter->temp' is allocated or relocated in tracefindnextentry() but not freed before 'trace_pipe' is closed.

To fix it, free 'iter->temp' in tracingreleasepipe().