Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 400 insertions, 0 deletions

diff --git a/fs/dlm/dir.c b/fs/dlm/dir.c
new file mode 100644
index 000000000..aa08e8f44
--- /dev/null
+++ b/fs/dlm/dir.c
@@ -0,0 +1,400 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "lowcomms.h"
+#include "rcom.h"
+#include "config.h"
+#include "memory.h"
+#include "recover.h"
+#include "util.h"
+#include "lock.h"
+#include "dir.h"
+
+/*
+ * We use the upper 16 bits of the hash value to select the directory node.
+ * Low bits are used for distribution of rsb's among hash buckets on each node.
+ *
+ * To give the exact range wanted (0 to num_nodes-1), we apply a modulus of
+ * num_nodes to the hash value.  This value in the desired range is used as an
+ * offset into the sorted list of nodeid's to give the particular nodeid.
+ */
+
+int dlm_hash2nodeid(struct dlm_ls *ls, uint32_t hash)
+{
+	uint32_t node;
+
+	if (ls->ls_num_nodes == 1)
+		return dlm_our_nodeid();
+	else {
+		node = (hash >> 16) % ls->ls_total_weight;
+		return ls->ls_node_array[node];
+	}
+}
+
+int dlm_dir_nodeid(struct dlm_rsb *r)
+{
+	return r->res_dir_nodeid;
+}
+
+void dlm_recover_dir_nodeid(struct dlm_ls *ls, const struct list_head *root_list)
+{
+	struct dlm_rsb *r;
+
+	list_for_each_entry(r, root_list, res_root_list) {
+		r->res_dir_nodeid = dlm_hash2nodeid(ls, r->res_hash);
+	}
+}
+
+int dlm_recover_directory(struct dlm_ls *ls, uint64_t seq)
+{
+	struct dlm_member *memb;
+	char *b, *last_name = NULL;
+	int error = -ENOMEM, last_len, nodeid, result;
+	uint16_t namelen;
+	unsigned int count = 0, count_bad = 0, count_add = 0;
+
+	log_rinfo(ls, "dlm_recover_directory");
+
+	if (dlm_no_directory(ls))
+		goto out_status;
+
+	last_name = kmalloc(DLM_RESNAME_MAXLEN, GFP_NOFS);
+	if (!last_name)
+		goto out;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (memb->nodeid == dlm_our_nodeid())
+			continue;
+
+		memset(last_name, 0, DLM_RESNAME_MAXLEN);
+		last_len = 0;
+
+		for (;;) {
+			int left;
+			if (dlm_recovery_stopped(ls)) {
+				error = -EINTR;
+				goto out_free;
+			}
+
+			error = dlm_rcom_names(ls, memb->nodeid,
+					       last_name, last_len, seq);
+			if (error)
+				goto out_free;
+
+			cond_resched();
+
+			/*
+			 * pick namelen/name pairs out of received buffer
+			 */
+
+			b = ls->ls_recover_buf->rc_buf;
+			left = le16_to_cpu(ls->ls_recover_buf->rc_header.h_length);
+			left -= sizeof(struct dlm_rcom);
+
+			for (;;) {
+				__be16 v;
+
+				error = -EINVAL;
+				if (left < sizeof(__be16))
+					goto out_free;
+
+				memcpy(&v, b, sizeof(__be16));
+				namelen = be16_to_cpu(v);
+				b += sizeof(__be16);
+				left -= sizeof(__be16);
+
+				/* namelen of 0xFFFFF marks end of names for
+				   this node; namelen of 0 marks end of the
+				   buffer */
+
+				if (namelen == 0xFFFF)
+					goto done;
+				if (!namelen)
+					break;
+
+				if (namelen > left)
+					goto out_free;
+
+				if (namelen > DLM_RESNAME_MAXLEN)
+					goto out_free;
+
+				error = dlm_master_lookup(ls, memb->nodeid,
+							  b, namelen,
+							  DLM_LU_RECOVER_DIR,
+							  &nodeid, &result);
+				if (error) {
+					log_error(ls, "recover_dir lookup %d",
+						  error);
+					goto out_free;
+				}
+
+				/* The name was found in rsbtbl, but the
+				 * master nodeid is different from
+				 * memb->nodeid which says it is the master.
+				 * This should not happen. */
+
+				if (result == DLM_LU_MATCH &&
+				    nodeid != memb->nodeid) {
+					count_bad++;
+					log_error(ls, "recover_dir lookup %d "
+						  "nodeid %d memb %d bad %u",
+						  result, nodeid, memb->nodeid,
+						  count_bad);
+					print_hex_dump_bytes("dlm_recover_dir ",
+							     DUMP_PREFIX_NONE,
+							     b, namelen);
+				}
+
+				/* The name was found in rsbtbl, and the
+				 * master nodeid matches memb->nodeid.
+
+				if (result == DLM_LU_MATCH &&
+				    nodeid == memb->nodeid) {
+					count_match++;
+				}*/
+
+				/* The name was not found in rsbtbl and was
+				 * added with memb->nodeid as the master. */
+
+				if (result == DLM_LU_ADD) {
+					count_add++;
+				}
+
+				last_len = namelen;
+				memcpy(last_name, b, namelen);
+				b += namelen;
+				left -= namelen;
+				count++;
+			}
+		}
+	 done:
+		;
+	}
+
+ out_status:
+	error = 0;
+	dlm_set_recover_status(ls, DLM_RS_DIR);
+
+	log_rinfo(ls, "dlm_recover_directory %u in %u new",
+		  count, count_add);
+ out_free:
+	kfree(last_name);
+ out:
+	return error;
+}
+
+static struct dlm_rsb *find_rsb_root(struct dlm_ls *ls, const char *name,
+				     int len)
+{
+	struct dlm_rsb *r;
+	int rv;
+
+	read_lock_bh(&ls->ls_rsbtbl_lock);
+	rv = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
+	read_unlock_bh(&ls->ls_rsbtbl_lock);
+	if (!rv)
+		return r;
+
+	list_for_each_entry(r, &ls->ls_masters_list, res_masters_list) {
+		if (len == r->res_length && !memcmp(name, r->res_name, len)) {
+			log_debug(ls, "find_rsb_root revert to root_list %s",
+				  r->res_name);
+			return r;
+		}
+	}
+	return NULL;
+}
+
+struct dlm_dir_dump {
+	/* init values to match if whole
+	 * dump fits to one seq. Sanity check only.
+	 */
+	uint64_t seq_init;
+	uint64_t nodeid_init;
+	/* compare local pointer with last lookup,
+	 * just a sanity check.
+	 */
+	struct list_head *last;
+
+	unsigned int sent_res; /* for log info */
+	unsigned int sent_msg; /* for log info */
+
+	struct list_head list;
+};
+
+static void drop_dir_ctx(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_dir_dump *dd, *safe;
+
+	write_lock_bh(&ls->ls_dir_dump_lock);
+	list_for_each_entry_safe(dd, safe, &ls->ls_dir_dump_list, list) {
+		if (dd->nodeid_init == nodeid) {
+			log_error(ls, "drop dump seq %llu",
+				 (unsigned long long)dd->seq_init);
+			list_del(&dd->list);
+			kfree(dd);
+		}
+	}
+	write_unlock_bh(&ls->ls_dir_dump_lock);
+}
+
+static struct dlm_dir_dump *lookup_dir_dump(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_dir_dump *iter, *dd = NULL;
+
+	read_lock_bh(&ls->ls_dir_dump_lock);
+	list_for_each_entry(iter, &ls->ls_dir_dump_list, list) {
+		if (iter->nodeid_init == nodeid) {
+			dd = iter;
+			break;
+		}
+	}
+	read_unlock_bh(&ls->ls_dir_dump_lock);
+
+	return dd;
+}
+
+static struct dlm_dir_dump *init_dir_dump(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_dir_dump *dd;
+
+	dd = lookup_dir_dump(ls, nodeid);
+	if (dd) {
+		log_error(ls, "found ongoing dir dump for node %d, will drop it",
+			  nodeid);
+		drop_dir_ctx(ls, nodeid);
+	}
+
+	dd = kzalloc_obj(*dd, GFP_ATOMIC);
+	if (!dd)
+		return NULL;
+
+	dd->seq_init = ls->ls_recover_seq;
+	dd->nodeid_init = nodeid;
+
+	write_lock_bh(&ls->ls_dir_dump_lock);
+	list_add(&dd->list, &ls->ls_dir_dump_list);
+	write_unlock_bh(&ls->ls_dir_dump_lock);
+
+	return dd;
+}
+
+/* Find the rsb where we left off (or start again), then send rsb names
+   for rsb's we're master of and whose directory node matches the requesting
+   node.  inbuf is the rsb name last sent, inlen is the name's length */
+
+void dlm_copy_master_names(struct dlm_ls *ls, const char *inbuf, int inlen,
+ 			   char *outbuf, int outlen, int nodeid)
+{
+	struct list_head *list;
+	struct dlm_rsb *r;
+	int offset = 0, dir_nodeid;
+	struct dlm_dir_dump *dd;
+	__be16 be_namelen;
+
+	read_lock_bh(&ls->ls_masters_lock);
+
+	if (inlen > 1) {
+		dd = lookup_dir_dump(ls, nodeid);
+		if (!dd) {
+			log_error(ls, "failed to lookup dir dump context nodeid: %d",
+				  nodeid);
+			goto out;
+		}
+
+		/* next chunk in dump */
+		r = find_rsb_root(ls, inbuf, inlen);
+		if (!r) {
+			log_error(ls, "copy_master_names from %d start %d %.*s",
+				  nodeid, inlen, inlen, inbuf);
+			goto out;
+		}
+		list = r->res_masters_list.next;
+
+		/* sanity checks */
+		if (dd->last != &r->res_masters_list ||
+		    dd->seq_init != ls->ls_recover_seq) {
+			log_error(ls, "failed dir dump sanity check seq_init: %llu seq: %llu",
+				  (unsigned long long)dd->seq_init,
+				  (unsigned long long)ls->ls_recover_seq);
+			goto out;
+		}
+	} else {
+		dd = init_dir_dump(ls, nodeid);
+		if (!dd) {
+			log_error(ls, "failed to allocate dir dump context");
+			goto out;
+		}
+
+		/* start dump */
+		list = ls->ls_masters_list.next;
+		dd->last = list;
+	}
+
+	for (offset = 0; list != &ls->ls_masters_list; list = list->next) {
+		r = list_entry(list, struct dlm_rsb, res_masters_list);
+		dir_nodeid = dlm_dir_nodeid(r);
+		if (dir_nodeid != nodeid)
+			continue;
+
+		/*
+		 * The block ends when we can't fit the following in the
+		 * remaining buffer space:
+		 * namelen (uint16_t) +
+		 * name (r->res_length) +
+		 * end-of-block record 0x0000 (uint16_t)
+		 */
+
+		if (offset + sizeof(uint16_t)*2 + r->res_length > outlen) {
+			/* Write end-of-block record */
+			be_namelen = cpu_to_be16(0);
+			memcpy(outbuf + offset, &be_namelen, sizeof(__be16));
+			offset += sizeof(__be16);
+			dd->sent_msg++;
+			goto out;
+		}
+
+		be_namelen = cpu_to_be16(r->res_length);
+		memcpy(outbuf + offset, &be_namelen, sizeof(__be16));
+		offset += sizeof(__be16);
+		memcpy(outbuf + offset, r->res_name, r->res_length);
+		offset += r->res_length;
+		dd->sent_res++;
+		dd->last = list;
+	}
+
+	/*
+	 * If we've reached the end of the list (and there's room) write a
+	 * terminating record.
+	 */
+
+	if ((list == &ls->ls_masters_list) &&
+	    (offset + sizeof(uint16_t) <= outlen)) {
+		/* end dump */
+		be_namelen = cpu_to_be16(0xFFFF);
+		memcpy(outbuf + offset, &be_namelen, sizeof(__be16));
+		offset += sizeof(__be16);
+		dd->sent_msg++;
+		log_rinfo(ls, "dlm_recover_directory nodeid %d sent %u res out %u messages",
+			  nodeid, dd->sent_res, dd->sent_msg);
+
+		write_lock_bh(&ls->ls_dir_dump_lock);
+		list_del_init(&dd->list);
+		write_unlock_bh(&ls->ls_dir_dump_lock);
+		kfree(dd);
+	}
+ out:
+	read_unlock_bh(&ls->ls_masters_lock);
+}
+