[PATCH] fix double free issue in event_read_print_args

commit cb227dfc63346a23fd019f2146b4f9f4f5a58b6a (HEAD -> fix_double_free)
Author: Tw <[email protected]>
Date:   Thu Jun 27 14:40:09 2024 +0800

    Fix double free issue in event_read_print_args

    The corner case is that when we encounter a invalid right argument
of a condition operation.
    Currently, we free token immediately, but it will also be freed
when free `arg->op.op`.

    BTW, the crash calltrace as follows:

    Program received signal SIGSEGV, Segmentation fault.
    get_meta (p=<optimized out>) at
/home/tw/code/zig/build/stage3/lib/zig/libc/musl/src/malloc/mallocng/meta.h:141
    141     /home/tw/code/zig/build/stage3/lib/zig/libc/musl/src/malloc/mallocng/meta.h:
No such file or directory.
    (gdb) bt
        at /home/tw/code/zig/build/stage3/lib/zig/libc/musl/src/malloc/mallocng/meta.h:141
        at /home/tw/code/zig/build/stage3/lib/zig/libc/musl/src/malloc/mallocng/free.c:105
        at /tmp/.cache/zig/p/12207a2e4477bf4414e7df3eb2172c698ab916695a0d3eefbf16f65b0c969dd81184/src/event-parse.c:1128
        list@entry=0x7ff7b18768)
        at /tmp/.cache/zig/p/12207a2e4477bf4414e7df3eb2172c698ab916695a0d3eefbf16f65b0c969dd81184/src/event-parse.c:1417
        at /tmp/.cache/zig/p/12207a2e4477bf4414e7df3eb2172c698ab916695a0d3eefbf16f65b0c969dd81184/src/event-parse.c:3895
        sys=<optimized out>)
        at /tmp/.cache/zig/p/12207a2e4477bf4414e7df3eb2172c698ab916695a0d3eefbf16f65b0c969dd81184/src/event-parse.c:7824
        size=<optimized out>, sys=sys@entry=0x7ff7ff51c0 "kvm")
        at /tmp/.cache/zig/p/12207a2e4477bf4414e7df3eb2172c698ab916695a0d3eefbf16f65b0c969dd81184/src/event-parse.c:7882
        buf=0x7ff7b0c610 "kvm_sys_access", size=549616874800,
sys=0x7fffffe0b2 "me", sys@entry=0x7ff7ff51c0 "kvm")
        at /tmp/.cache/zig/p/12207a2e4477bf4414e7df3eb2172c698ab916695a0d3eefbf16f65b0c969dd81184/src/event-parse.c:7945
        tracing_dir=tracing_dir@entry=0x7ff7ffc660
"/sys/kernel/tracing", system=system@entry=0x7ff7ff51c0 "kvm",
        check=false)
        at /tmp/.cache/zig/p/1220c1c006cbf05434d240b65f343c84f3d7f837fbef31f2cade733ec911cc3ed76b/src/tracefs-events.c:1062
        system=0x7ff7ff51c0 "kvm")
        at /tmp/.cache/zig/p/1220c1c006cbf05434d240b65f343c84f3d7f837fbef31f2cade733ec911cc3ed76b/src/tracefs-events.c:1084
        tep=tep@entry=0x7ff7ffc830, sys_names=sys_names@entry=0x0,
parsing_failures=0x0,
        parsing_failures@entry=0x7fffffe7b0)
        at /tmp/.cache/zig/p/1220c1c006cbf05434d240b65f343c84f3d7f837fbef31f2cade733ec911cc3ed76b/src/tracefs-events.c:1284
        sys_names@entry=0x7ffffff880)
        at /tmp/.cache/zig/p/1220c1c006cbf05434d240b65f343c84f3d7f837fbef31f2cade733ec911cc3ed76b/src/tracefs-events.c:1355
        tracing_dir=0x6500006c6f6f62 <error: Cannot access memory at
address 0x6500006c6f6f62>)
        at /tmp/.cache/zig/p/1220c1c006cbf05434d240b65f343c84f3d7f837fbef31f2cade733ec911cc3ed76b/src/tracefs-events.c:1377

    Signed-off-by: Tw <[email protected]>