diff options
Diffstat (limited to 'poky/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch')
| -rw-r--r-- | poky/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/poky/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch b/poky/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch new file mode 100644 index 0000000000..7a10131bad --- /dev/null +++ b/poky/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch @@ -0,0 +1,276 @@ +From 83b5323261bb72313bffcf37476c1b8f0847c736 Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Wed, 15 Sep 2021 15:16:19 +0100 +Subject: [PATCH] elf: Avoid deadlock between pthread_create and ctors [BZ + #28357] + +The fix for bug 19329 caused a regression such that pthread_create can +deadlock when concurrent ctors from dlopen are waiting for it to finish. +Use a new GL(dl_load_tls_lock) in pthread_create that is not taken +around ctors in dlopen. + +The new lock is also used in __tls_get_addr instead of GL(dl_load_lock). + +The new lock is held in _dl_open_worker and _dl_close_worker around +most of the logic before/after the init/fini routines. When init/fini +routines are running then TLS is in a consistent, usable state. +In _dl_open_worker the new lock requires catching and reraising dlopen +failures that happen in the critical section. + +The new lock is reinitialized in a fork child, to keep the existing +behaviour and it is kept recursive in case malloc interposition or TLS +access from signal handlers can retake it. It is not obvious if this +is necessary or helps, but avoids changing the preexisting behaviour. + +The new lock may be more appropriate for dl_iterate_phdr too than +GL(dl_load_write_lock), since TLS state of an incompletely loaded +module may be accessed. If the new lock can replace the old one, +that can be a separate change. + +Fixes bug 28357. + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + elf/dl-close.c | 6 ++ + elf/dl-open.c | 35 ++++++++- + elf/dl-support.c | 7 ++ + elf/dl-tls.c | 16 ++--- + elf/rtld.c | 1 + + sysdeps/nptl/fork.c | 3 + + sysdeps/generic/ldsodefs.h | 9 ++- + 10 files changed, 235 insertions(+), 12 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=024a7640ab9ecea80e527f4e4d7f7a1868e952c5] +Comment: This patch is refreshed for glibc 2.31. In upstream glibc 2.34 multiple src files are shuffled, updated this patch as per the code present in glibc 2.31. Removed test case. +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/dl-close.c b/elf/dl-close.c +index 93ff5c96e9..cfe0f1c0c9 100644 +--- a/elf/dl-close.c ++++ b/elf/dl-close.c +@@ -551,6 +551,9 @@ + size_t tls_free_end; + tls_free_start = tls_free_end = NO_TLS_OFFSET; + ++ /* Protects global and module specitic TLS state. */ ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); ++ + /* We modify the list of loaded objects. */ + __rtld_lock_lock_recursive (GL(dl_load_write_lock)); + +@@ -786,6 +789,9 @@ + GL(dl_tls_static_used) = tls_free_start; + } + ++ /* TLS is cleaned up for the unloaded modules. */ ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); ++ + #ifdef SHARED + /* Auditing checkpoint: we have deleted all objects. */ + if (__glibc_unlikely (do_audit)) +diff --git a/elf/dl-open.c b/elf/dl-open.c +index 5295e931b0..6ea5dd2457 100644 +--- a/elf/dl-open.c ++++ b/elf/dl-open.c +@@ -57,6 +57,9 @@ + (non-negative). */ + unsigned int original_global_scope_pending_adds; + ++ /* Set to true if the end of dl_open_worker_begin was reached. */ ++ bool worker_continue; ++ + /* Original parameters to the program and the current environment. */ + int argc; + char **argv; +@@ -473,7 +473,7 @@ + } + + static void +-dl_open_worker (void *a) ++dl_open_worker_begin (void *a) + { + struct dl_open_args *args = a; + const char *file = args->file; +@@ -747,6 +747,36 @@ + if (mode & RTLD_GLOBAL) + add_to_global_resize (new); + ++ args->worker_continue = true; ++} ++ ++static void ++dl_open_worker (void *a) ++{ ++ struct dl_open_args *args = a; ++ ++ args->worker_continue = false; ++ ++ { ++ /* Protects global and module specific TLS state. */ ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); ++ ++ struct dl_exception ex; ++ int err = _dl_catch_exception (&ex, dl_open_worker_begin, args); ++ ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); ++ ++ if (__glibc_unlikely (ex.errstring != NULL)) ++ /* Reraise the error. */ ++ _dl_signal_exception (err, &ex, NULL); ++ } ++ ++ if (!args->worker_continue) ++ return; ++ ++ int mode = args->mode; ++ struct link_map *new = args->map; ++ + /* Run the initializer functions of new objects. Temporarily + disable the exception handler, so that lazy binding failures are + fatal. */ +diff --git a/elf/dl-support.c b/elf/dl-support.c +index 02e2ed72f5..d99c1f1d62 100644 +--- a/elf/dl-support.c ++++ b/elf/dl-support.c +@@ -219,6 +219,13 @@ + list of loaded objects while an object is added to or removed from + that list. */ + __rtld_lock_define_initialized_recursive (, _dl_load_write_lock) ++/* This lock protects global and module specific TLS related data. ++ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), ++ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are ++ accessed and when TLS related relocations are processed for a ++ module. It was introduced to keep pthread_create accessing TLS ++ state that is being set up. */ ++__rtld_lock_define_initialized_recursive (, _dl_load_tls_lock) + + + #ifdef HAVE_AUX_VECTOR +diff --git a/elf/dl-tls.c b/elf/dl-tls.c +index d554ae4497..9260d2d696 100644 +--- a/elf/dl-tls.c ++++ b/elf/dl-tls.c +@@ -443,7 +443,7 @@ + size_t maxgen = 0; + + /* Protects global dynamic TLS related state. */ +- __rtld_lock_lock_recursive (GL(dl_load_lock)); ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); + + /* Check if the current dtv is big enough. */ + if (dtv[-1].counter < GL(dl_tls_max_dtv_idx)) +@@ -517,7 +517,7 @@ + listp = listp->next; + assert (listp != NULL); + } +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + + /* The DTV version is up-to-date now. */ + dtv[0].counter = maxgen; +@@ -656,7 +656,7 @@ + + Here the dtv needs to be updated to new_gen generation count. + +- This code may be called during TLS access when GL(dl_load_lock) ++ This code may be called during TLS access when GL(dl_load_tls_lock) + is not held. In that case the user code has to synchronize with + dlopen and dlclose calls of relevant modules. A module m is + relevant if the generation of m <= new_gen and dlclose of m is +@@ -778,11 +778,11 @@ + if (__glibc_unlikely (the_map->l_tls_offset + != FORCED_DYNAMIC_TLS_OFFSET)) + { +- __rtld_lock_lock_recursive (GL(dl_load_lock)); ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); + if (__glibc_likely (the_map->l_tls_offset == NO_TLS_OFFSET)) + { + the_map->l_tls_offset = FORCED_DYNAMIC_TLS_OFFSET; +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + } + else if (__glibc_likely (the_map->l_tls_offset + != FORCED_DYNAMIC_TLS_OFFSET)) +@@ -794,7 +794,7 @@ + #else + # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" + #endif +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + + dtv[GET_ADDR_MODULE].pointer.to_free = NULL; + dtv[GET_ADDR_MODULE].pointer.val = p; +@@ -802,7 +802,7 @@ + return (char *) p + GET_ADDR_OFFSET; + } + else +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + } + struct dtv_pointer result = allocate_and_init (the_map); + dtv[GET_ADDR_MODULE].pointer = result; +@@ -873,7 +873,7 @@ + return NULL; + + dtv_t *dtv = THREAD_DTV (); +- /* This may be called without holding the GL(dl_load_lock). Reading ++ /* This may be called without holding the GL(dl_load_tls_lock). Reading + arbitrary gen value is fine since this is best effort code. */ + size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); + if (__glibc_unlikely (dtv[0].counter != gen)) +diff --git a/elf/rtld.c b/elf/rtld.c +index 8d2bba3d43..9642eb9c92 100644 +--- a/elf/rtld.c ++++ b/elf/rtld.c +@@ -283,6 +283,7 @@ + #ifdef _LIBC_REENTRANT + ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, + ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, ++ ._dl_load_tls_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, + #endif + ._dl_nns = 1, + ._dl_ns = +diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c +index c471f7b15f..021691b9b7 100644 +--- a/sysdeps/nptl/fork.c ++++ b/sysdeps/nptl/fork.c +@@ -125,6 +125,9 @@ + /* Reset the lock the dynamic loader uses to protect its data. */ + __rtld_lock_initialize (GL(dl_load_lock)); + ++ /* Reset the lock protecting dynamic TLS related data. */ ++ __rtld_lock_initialize (GL(dl_load_tls_lock)); ++ + /* Run the handlers registered for the child. */ + __run_fork_handlers (atfork_run_child, multiple_threads); + } +diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h +index d49529da0d..9ec1511bb0 100644 +--- a/sysdeps/generic/ldsodefs.h ++++ b/sysdeps/generic/ldsodefs.h +@@ -369,6 +369,13 @@ + list of loaded objects while an object is added to or removed + from that list. */ + __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock) ++ /* This lock protects global and module specific TLS related data. ++ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), ++ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are ++ accessed and when TLS related relocations are processed for a ++ module. It was introduced to keep pthread_create accessing TLS ++ state that is being set up. */ ++ __rtld_lock_define_recursive (EXTERN, _dl_load_tls_lock) + + /* Incremented whenever something may have been added to dl_loaded. */ + EXTERN unsigned long long _dl_load_adds; +@@ -1153,7 +1160,7 @@ + + /* Add module to slot information data. If DO_ADD is false, only the + required memory is allocated. Must be called with GL +- (dl_load_lock) acquired. If the function has already been called ++ (dl_load_tls_lock) acquired. If the function has already been called + for the link map L with !do_add, then this function will not raise + an exception, otherwise it is possible that it encounters a memory + allocation failure. */ +-- +2.27.0 |