Merge branch 'for-5.20/io_uring' into for-5.20/io_uring-zerocopy-send

* for-5.20/io_uring: (716 commits)
  io_uring: ensure REQ_F_ISREG is set async offload
  net: fix compat pointer in get_compat_msghdr()
  io_uring: Don't require reinitable percpu_ref
  io_uring: fix types in io_recvmsg_multishot_overflow
  io_uring: Use atomic_long_try_cmpxchg in __io_account_mem
  io_uring: support multishot in recvmsg
  net: copy from user before calling __get_compat_msghdr
  net: copy from user before calling __copy_msghdr
  io_uring: support 0 length iov in buffer select in compat
  io_uring: fix multishot ending when not polled
  io_uring: add netmsg cache
  io_uring: impose max limit on apoll cache
  io_uring: add abstraction around apoll cache
  io_uring: move apoll cache to poll.c
  io_uring: consolidate hash_locked io-wq handling
  io_uring: clear REQ_F_HASH_LOCKED on hash removal
  io_uring: don't race double poll setting REQ_F_ASYNC_DATA
  io_uring: don't miss setting REQ_F_DOUBLE_POLL
  io_uring: disable multishot recvmsg
  io_uring: only trace one of complete or overflow
  ...

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 22 insertions, 13 deletions

diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
index 3e11523bc6f6..77e75bead569 100644
--- a/kernel/module/kallsyms.c
+++ b/kernel/module/kallsyms.c
@@ -137,6 +137,7 @@ void layout_symtab(struct module *mod, struct load_info *info)
 	info->symoffs = ALIGN(mod->data_layout.size, symsect->sh_addralign ?: 1);
 	info->stroffs = mod->data_layout.size = info->symoffs + ndst * sizeof(Elf_Sym);
 	mod->data_layout.size += strtab_size;
+	/* Note add_kallsyms() computes strtab_size as core_typeoffs - stroffs */
 	info->core_typeoffs = mod->data_layout.size;
 	mod->data_layout.size += ndst * sizeof(char);
 	mod->data_layout.size = strict_align(mod->data_layout.size);
@@ -169,19 +170,20 @@ void add_kallsyms(struct module *mod, const struct load_info *info)
 	Elf_Sym *dst;
 	char *s;
 	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
+	unsigned long strtab_size;
 
 	/* Set up to point into init section. */
 	mod->kallsyms = (void __rcu *)mod->init_layout.base +
 		info->mod_kallsyms_init_off;
 
-	preempt_disable();
+	rcu_read_lock();
 	/* The following is safe since this pointer cannot change */
-	rcu_dereference_sched(mod->kallsyms)->symtab = (void *)symsec->sh_addr;
-	rcu_dereference_sched(mod->kallsyms)->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
+	rcu_dereference(mod->kallsyms)->symtab = (void *)symsec->sh_addr;
+	rcu_dereference(mod->kallsyms)->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
 	/* Make sure we get permanent strtab: don't use info->strtab. */
-	rcu_dereference_sched(mod->kallsyms)->strtab =
+	rcu_dereference(mod->kallsyms)->strtab =
 		(void *)info->sechdrs[info->index.str].sh_addr;
-	rcu_dereference_sched(mod->kallsyms)->typetab = mod->init_layout.base + info->init_typeoffs;
+	rcu_dereference(mod->kallsyms)->typetab = mod->init_layout.base + info->init_typeoffs;
 
 	/*
 	 * Now populate the cut down core kallsyms for after init
@@ -190,22 +192,29 @@ void add_kallsyms(struct module *mod, const struct load_info *info)
 	mod->core_kallsyms.symtab = dst = mod->data_layout.base + info->symoffs;
 	mod->core_kallsyms.strtab = s = mod->data_layout.base + info->stroffs;
 	mod->core_kallsyms.typetab = mod->data_layout.base + info->core_typeoffs;
-	src = rcu_dereference_sched(mod->kallsyms)->symtab;
-	for (ndst = i = 0; i < rcu_dereference_sched(mod->kallsyms)->num_symtab; i++) {
-		rcu_dereference_sched(mod->kallsyms)->typetab[i] = elf_type(src + i, info);
+	strtab_size = info->core_typeoffs - info->stroffs;
+	src = rcu_dereference(mod->kallsyms)->symtab;
+	for (ndst = i = 0; i < rcu_dereference(mod->kallsyms)->num_symtab; i++) {
+		rcu_dereference(mod->kallsyms)->typetab[i] = elf_type(src + i, info);
 		if (i == 0 || is_livepatch_module(mod) ||
 		    is_core_symbol(src + i, info->sechdrs, info->hdr->e_shnum,
 				   info->index.pcpu)) {
+			ssize_t ret;
+
 			mod->core_kallsyms.typetab[ndst] =
-			    rcu_dereference_sched(mod->kallsyms)->typetab[i];
+			    rcu_dereference(mod->kallsyms)->typetab[i];
 			dst[ndst] = src[i];
 			dst[ndst++].st_name = s - mod->core_kallsyms.strtab;
-			s += strscpy(s,
-				     &rcu_dereference_sched(mod->kallsyms)->strtab[src[i].st_name],
-				     KSYM_NAME_LEN) + 1;
+			ret = strscpy(s,
+				      &rcu_dereference(mod->kallsyms)->strtab[src[i].st_name],
+				      strtab_size);
+			if (ret < 0)
+				break;
+			s += ret + 1;
+			strtab_size -= ret + 1;
 		}
 	}
-	preempt_enable();
+	rcu_read_unlock();
 	mod->core_kallsyms.num_symtab = ndst;
 }