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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2020-07-06 10:21:16 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2020-07-06 10:21:16 +0200 |
| commit | 0c76fc3c2b346dc5401dc055d97d4279632b0fb3 (patch) | |
| tree | 67d7a99ad801c38a137fbb9d08ac54137bb901b9 /elf/libc_early_init.c | |
| parent | f9cf87353772ca370b7bb901d86365a564fba49f (diff) | |
| download | glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.tar.gz glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.tar.xz glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.zip | |
Linux: Perform rseq registration at C startup and thread creation
Register rseq TLS for each thread (including main), and unregister for each thread (excluding main). "rseq" stands for Restartable Sequences. See the rseq(2) man page proposed here: https://lkml.org/lkml/2018/9/19/647 Those are based on glibc master branch commit 3ee1e0ec5c. The rseq system call was merged into Linux 4.18. The TLS_STATIC_SURPLUS define is increased to leave additional room for dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working. The increase (76 bytes) is larger than 32 bytes because it has not been increased in quite a while. The cost in terms of additional TLS storage is quite significant, but it will also obscure some initial-exec-related dlopen failures.
Diffstat (limited to 'elf/libc_early_init.c')
| -rw-r--r-- | elf/libc_early_init.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/elf/libc_early_init.c b/elf/libc_early_init.c index e6c64fb526..f0fcf6448e 100644 --- a/elf/libc_early_init.c +++ b/elf/libc_early_init.c @@ -18,10 +18,14 @@ #include <ctype.h> #include <libc-early-init.h> +#include <rseq-internal.h> void __libc_early_init (_Bool initial) { /* Initialize ctype data. */ __ctype_init (); + /* Register rseq ABI to the kernel for the main program's libc. */ + if (initial) + rseq_register_current_thread (); } |