Date: Fri, 9 Apr 2021 20:47:16 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 895080484248 - main - rtld: allow to use tls_get_addr_slow() from context where rtld_bind_lock is locked Message-ID: <202104092047.139KlGML071633@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=89508048424837ffdb32c8444dab02261711f77d commit 89508048424837ffdb32c8444dab02261711f77d Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2021-04-06 18:56:58 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2021-04-09 20:46:24 +0000 rtld: allow to use tls_get_addr_slow() from context where rtld_bind_lock is locked Explicit locked parameter is added Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D29623 --- libexec/rtld-elf/rtld.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c index 8b03616993d2..8c8271abc93e 100644 --- a/libexec/rtld-elf/rtld.c +++ b/libexec/rtld-elf/rtld.c @@ -166,6 +166,7 @@ static int symlook_list(SymLook *, const Objlist *, DoneList *); static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); +static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; static void trace_loaded_objects(Obj_Entry *); static void unlink_object(Obj_Entry *); static void unload_object(Obj_Entry *, RtldLockState *lockstate); @@ -4871,9 +4872,8 @@ unref_dag(Obj_Entry *root) /* * Common code for MD __tls_get_addr(). */ -static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; static void * -tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) +tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) { Elf_Addr *newdtv, *dtv; RtldLockState lockstate; @@ -4882,7 +4882,8 @@ tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) dtv = *dtvp; /* Check dtv generation in case new modules have arrived */ if (dtv[0] != tls_dtv_generation) { - wlock_acquire(rtld_bind_lock, &lockstate); + if (!locked) + wlock_acquire(rtld_bind_lock, &lockstate); newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); to_copy = dtv[1]; if (to_copy > tls_max_index) @@ -4891,17 +4892,20 @@ tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) newdtv[0] = tls_dtv_generation; newdtv[1] = tls_max_index; free(dtv); - lock_release(rtld_bind_lock, &lockstate); + if (!locked) + lock_release(rtld_bind_lock, &lockstate); dtv = *dtvp = newdtv; } /* Dynamically allocate module TLS if necessary */ if (dtv[index + 1] == 0) { /* Signal safe, wlock will block out signals. */ - wlock_acquire(rtld_bind_lock, &lockstate); + if (!locked) + wlock_acquire(rtld_bind_lock, &lockstate); if (!dtv[index + 1]) dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); - lock_release(rtld_bind_lock, &lockstate); + if (!locked) + lock_release(rtld_bind_lock, &lockstate); } return ((void *)(dtv[index + 1] + offset)); } @@ -4916,7 +4920,7 @@ tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) if (__predict_true(dtv[0] == tls_dtv_generation && dtv[index + 1] != 0)) return ((void *)(dtv[index + 1] + offset)); - return (tls_get_addr_slow(dtvp, index, offset)); + return (tls_get_addr_slow(dtvp, index, offset, false)); } #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
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