Mercurial > hg > nginx
changeset 4489:9806bf07d119
Event pipe: fixed buffer loss in p->length case.
With previous code raw buffer might be lost if p->input_filter() was called
on a buffer without any data and used ngx_event_pipe_add_free_buf() to
return it to the free list. This eventually might cause "all buffers busy"
problem, resulting in segmentation fault due to null pointer dereference in
ngx_event_pipe_write_chain_to_temp_file().
In ngx_event_pipe_add_free_buf() the buffer was added to the list start
due to pos == last, and then "p->free_raw_bufs = cl->next" in
ngx_event_pipe_read_upstream() dropped both chain links to the buffer
from the p->free_raw_bufs list.
Fix is to move "p->free_raw_bufs = cl->next" before calling the
p->input_filter().
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 22 Feb 2012 11:28:53 +0000 |
parents | d33ce8cd0d70 |
children | 0cc1b430a0e6 |
files | src/event/ngx_event_pipe.c |
diffstat | 1 files changed, 2 insertions(+), 1 deletions(-) [+] |
line wrap: on
line diff
--- a/src/event/ngx_event_pipe.c Tue Feb 21 15:10:13 2012 +0000 +++ b/src/event/ngx_event_pipe.c Wed Feb 22 11:28:53 2012 +0000 @@ -401,13 +401,14 @@ if (cl->buf->last - cl->buf->pos >= p->length) { + p->free_raw_bufs = cl->next; + /* STUB */ cl->buf->num = p->num++; if (p->input_filter(p, cl->buf) == NGX_ERROR) { return NGX_ABORT; } - p->free_raw_bufs = cl->next; ngx_free_chain(p->pool, cl); } }