diff options
author | Florian Weimer <fweimer@redhat.com> | 2022-08-15 16:45:40 +0200 |
---|---|---|
committer | Florian Weimer <fweimer@redhat.com> | 2022-08-15 16:45:40 +0200 |
commit | 85860ad6eaf4c9739318f6b2a1ff7c2fa6b12ab5 (patch) | |
tree | df93f85338333de44d8ee2002ff855da0927c573 /inet/netinet | |
parent | f82e05ebb295cadd35f7372f652c72264da810ad (diff) | |
download | glibc-85860ad6eaf4c9739318f6b2a1ff7c2fa6b12ab5.tar.gz glibc-85860ad6eaf4c9739318f6b2a1ff7c2fa6b12ab5.tar.xz glibc-85860ad6eaf4c9739318f6b2a1ff7c2fa6b12ab5.zip |
malloc: Do not use MAP_NORESERVE to allocate heap segments
Address space for heap segments is reserved in a mmap call with MAP_ANONYMOUS | MAP_PRIVATE and protection flags PROT_NONE. This reservation does not count against the RSS limit of the process or system. Backing memory is allocated using mprotect in alloc_new_heap and grow_heap, and at this point, the allocator expects the kernel to provide memory (subject to memory overcommit). The SIGSEGV that might generate due to MAP_NORESERVE (according to the mmap manual page) does not seem to occur in practice, it's always SIGKILL from the OOM killer. Even if there is a way that SIGSEGV could be generated, it is confusing to applications that this only happens for secondary heaps, not for large mmap-based allocations, and not for the main arena. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Diffstat (limited to 'inet/netinet')
0 files changed, 0 insertions, 0 deletions