[CORE] Add MallocHookRun to call startMallocHook before RunElfInit#3999
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The `startMallocHook` function is only invoked inside `RunElfInit`, and
`RunElfInit` is only called for the main ELF binary within `__libc_start_main`.
In the `RunElfInit` function, `startMallocHook` is currently invoked only after
all initialization routines of dynamic libraries have been executed. However,
if the malloc hook is defined within a dependent library and that library’s
initialization routine invokes the malloc hook interface, activation of the
malloc hook will be delayed, leading to unexpected runtime exceptions.
Therefore, I add a call to `MallocHookRun` so that the malloc hook can be
available before the execution of library init functions.
Before:
```
__libc_start_main
|
---> RunElfInit
|
----> libA.so Init
| |
| ---> _Znam
| |
| ---> Native actual_malloc
---> startMallocHook
```
After:
```
__libc_start_main
|
---> MallocHookRun
| |
| ---> startMallocHook
|
---> RunElfInit
|
----> libA.so Init
|
---> _Znam
|
---> X86-64 real_malloc
```
Contributor
Author
|
I found this issue while analyzing startup crashes of x86-64 Linux WeChat (An IM app developed by Tencent) running on RISC-V Linux. |
Owner
|
Ok, make sense, thanks. |
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The
startMallocHookfunction is only invoked insideRunElfInit, andRunElfInitis only called for the main ELF binary within__libc_start_main.In the
RunElfInitfunction,startMallocHookis currently invoked only after all initialization routines of dynamic libraries have been executed. However, if the malloc hook is defined within a dependent library and that library’s initialization routine invokes the malloc hook interface, activation of the malloc hook will be delayed, leading to unexpected runtime exceptions.Therefore, I add a call to
MallocHookRunso that the malloc hook can be available before the execution of library init functions.Before:
After: