Merge tag 'core-rcu-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "These are the latest RCU updates for v5.12:

   - Documentation updates.

   - Miscellaneous fixes.

   - kfree_rcu() updates: Addition of mem_dump_obj() to provide
     allocator return addresses to more easily locate bugs. This has a
     couple of RCU-related commits, but is mostly MM. Was pulled in with
     akpm's agreement.

   - Per-callback-batch tracking of numbers of callbacks, which enables
     better debugging information and smarter reactions to large numbers
     of callbacks.

   - The first round of changes to allow CPUs to be runtime switched
     from and to callback-offloaded state.

   - CONFIG_PREEMPT_RT-related changes.

   - RCU CPU stall warning updates.

   - Addition of polling grace-period APIs for SRCU.

   - Torture-test and torture-test scripting updates, including a
     "torture everything" script that runs rcutorture, locktorture,
     scftorture, rcuscale, and refscale. Plus does an allmodconfig
     build.

   - nolibc fixes for the torture tests"

* tag 'core-rcu-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (130 commits)
  percpu_ref: Dump mem_dump_obj() info upon reference-count underflow
  rcu: Make call_rcu() print mem_dump_obj() info for double-freed callback
  mm: Make mem_obj_dump() vmalloc() dumps include start and length
  mm: Make mem_dump_obj() handle vmalloc() memory
  mm: Make mem_dump_obj() handle NULL and zero-sized pointers
  mm: Add mem_dump_obj() to print source of memory block
  tools/rcutorture: Fix position of -lgcc in mkinitrd.sh
  tools/nolibc: Fix position of -lgcc in the documented example
  tools/nolibc: Emit detailed error for missing alternate syscall number definitions
  tools/nolibc: Remove incorrect definitions of __ARCH_WANT_*
  tools/nolibc: Get timeval, timespec and timezone from linux/time.h
  tools/nolibc: Implement poll() based on ppoll()
  tools/nolibc: Implement fork() based on clone()
  tools/nolibc: Make getpgrp() fall back to getpgid(0)
  tools/nolibc: Make dup2() rely on dup3() when available
  tools/nolibc: Add the definition for dup()
  rcutorture: Add rcutree.use_softirq=0 to RUDE01 and TASKS01
  torture: Maintain torture-specific set of CPUs-online books
  torture: Clean up after torture-test CPU hotplugging
  rcutorture: Make object_debug also double call_rcu() heap object
  ...

1 files changed, 20 insertions, 0 deletions

diff --git a/mm/slab.c b/mm/slab.c
index d7c8da9319c7..dcc55e78f353 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3635,6 +3635,26 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
 EXPORT_SYMBOL(__kmalloc_node_track_caller);
 #endif /* CONFIG_NUMA */
 
+void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
+{
+	struct kmem_cache *cachep;
+	unsigned int objnr;
+	void *objp;
+
+	kpp->kp_ptr = object;
+	kpp->kp_page = page;
+	cachep = page->slab_cache;
+	kpp->kp_slab_cache = cachep;
+	objp = object - obj_offset(cachep);
+	kpp->kp_data_offset = obj_offset(cachep);
+	page = virt_to_head_page(objp);
+	objnr = obj_to_index(cachep, page, objp);
+	objp = index_to_obj(cachep, page, objnr);
+	kpp->kp_objp = objp;
+	if (DEBUG && cachep->flags & SLAB_STORE_USER)
+		kpp->kp_ret = *dbg_userword(cachep, objp);
+}
+
 /**
  * __do_kmalloc - allocate memory
  * @size: how many bytes of memory are required.