Actually, I'm not sure where is coredump; So I think l->alloc=NULL after free(l-alloc) is reasonable, because l->alloc's address can be reused in the pool. Of course, memzero after get mem from the pool can be solved about this question.But for example, ngx_array_push maybe reuse l->alloc's address, and ngx_array_push is not memzero from the start of get memory. So I think l->alloc=NULL after free(l-alloc) is necessary. Thanks for discussing this with me
At 2022-09-29 00:03:24, "Maxim Dounin" <mdou...@mdounin.ru> wrote: >Hello! > >On Wed, Sep 28, 2022 at 10:56:15AM +0800, zjd wrote: > >> my module is such: >> The pool is created with ngx_create_pool in >> module_init_process; I get momery from the pool in the start of >> each request, and then use ngx_reset_pool in the end of each >> request. >> The ngx_reset_pool take pool->large each alloc pointer return >> to pool, and each alloc pointer is wild pointer. >> And When another get momery from the pool in next request or >> next next request..., I maybe get wild pointer address and >> access inaccessible addresses, and then coredump. >> >> maybe the describe is simple in last mail. > >Ok, so from your description you are getting segfaults, and you >don't know why. > >Note that the ngx_reset_pool() function clears pool->large, and >also frees all the ngx_pool_large_t structures (since it resets >all pool blocks). That is, l->alloc you are clearing in your >patch is not expected to be used anywhere. If clearing it helps, >this suggests that there is a bug in your module which results in >this freed memory to be used somehow. > >While clearing l->alloc might appear to help, most likely it is >just hiding a bug in your module. Correct solution would be to >find the bug in your module and fix it. > >-- >Maxim Dounin >http://mdounin.ru/ >_______________________________________________ >nginx mailing list -- nginx@nginx.org >To unsubscribe send an email to nginx-le...@nginx.org
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