--- /dev/null
+From 968b71583130b6104c9f33ba60446d598e327a8b Mon Sep 17 00:00:00 2001
+From: Josef Bacik <josef@toxicpanda.com>
+Date: Fri, 14 Oct 2022 08:52:46 -0400
+Subject: btrfs: fix tree mod log mishandling of reallocated nodes
+
+From: Josef Bacik <josef@toxicpanda.com>
+
+commit 968b71583130b6104c9f33ba60446d598e327a8b upstream.
+
+We have been seeing the following panic in production
+
+ kernel BUG at fs/btrfs/tree-mod-log.c:677!
+ invalid opcode: 0000 [#1] SMP
+ RIP: 0010:tree_mod_log_rewind+0x1b4/0x200
+ RSP: 0000:ffffc9002c02f890 EFLAGS: 00010293
+ RAX: 0000000000000003 RBX: ffff8882b448c700 RCX: 0000000000000000
+ RDX: 0000000000008000 RSI: 00000000000000a7 RDI: ffff88877d831c00
+ RBP: 0000000000000002 R08: 000000000000009f R09: 0000000000000000
+ R10: 0000000000000000 R11: 0000000000100c40 R12: 0000000000000001
+ R13: ffff8886c26d6a00 R14: ffff88829f5424f8 R15: ffff88877d831a00
+ FS: 00007fee1d80c780(0000) GS:ffff8890400c0000(0000) knlGS:0000000000000000
+ CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+ CR2: 00007fee1963a020 CR3: 0000000434f33002 CR4: 00000000007706e0
+ DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
+ DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
+ PKRU: 55555554
+ Call Trace:
+ btrfs_get_old_root+0x12b/0x420
+ btrfs_search_old_slot+0x64/0x2f0
+ ? tree_mod_log_oldest_root+0x3d/0xf0
+ resolve_indirect_ref+0xfd/0x660
+ ? ulist_alloc+0x31/0x60
+ ? kmem_cache_alloc_trace+0x114/0x2c0
+ find_parent_nodes+0x97a/0x17e0
+ ? ulist_alloc+0x30/0x60
+ btrfs_find_all_roots_safe+0x97/0x150
+ iterate_extent_inodes+0x154/0x370
+ ? btrfs_search_path_in_tree+0x240/0x240
+ iterate_inodes_from_logical+0x98/0xd0
+ ? btrfs_search_path_in_tree+0x240/0x240
+ btrfs_ioctl_logical_to_ino+0xd9/0x180
+ btrfs_ioctl+0xe2/0x2ec0
+ ? __mod_memcg_lruvec_state+0x3d/0x280
+ ? do_sys_openat2+0x6d/0x140
+ ? kretprobe_dispatcher+0x47/0x70
+ ? kretprobe_rethook_handler+0x38/0x50
+ ? rethook_trampoline_handler+0x82/0x140
+ ? arch_rethook_trampoline_callback+0x3b/0x50
+ ? kmem_cache_free+0xfb/0x270
+ ? do_sys_openat2+0xd5/0x140
+ __x64_sys_ioctl+0x71/0xb0
+ do_syscall_64+0x2d/0x40
+
+Which is this code in tree_mod_log_rewind()
+
+ switch (tm->op) {
+ case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING:
+ BUG_ON(tm->slot < n);
+
+This occurs because we replay the nodes in order that they happened, and
+when we do a REPLACE we will log a REMOVE_WHILE_FREEING for every slot,
+starting at 0. 'n' here is the number of items in this block, which in
+this case was 1, but we had 2 REMOVE_WHILE_FREEING operations.
+
+The actual root cause of this was that we were replaying operations for
+a block that shouldn't have been replayed. Consider the following
+sequence of events
+
+1. We have an already modified root, and we do a btrfs_get_tree_mod_seq().
+2. We begin removing items from this root, triggering KEY_REPLACE for
+ it's child slots.
+3. We remove one of the 2 children this root node points to, thus triggering
+ the root node promotion of the remaining child, and freeing this node.
+4. We modify a new root, and re-allocate the above node to the root node of
+ this other root.
+
+The tree mod log looks something like this
+
+ logical 0 op KEY_REPLACE (slot 1) seq 2
+ logical 0 op KEY_REMOVE (slot 1) seq 3
+ logical 0 op KEY_REMOVE_WHILE_FREEING (slot 0) seq 4
+ logical 4096 op LOG_ROOT_REPLACE (old logical 0) seq 5
+ logical 8192 op KEY_REMOVE_WHILE_FREEING (slot 1) seq 6
+ logical 8192 op KEY_REMOVE_WHILE_FREEING (slot 0) seq 7
+ logical 0 op LOG_ROOT_REPLACE (old logical 8192) seq 8
+
+>From here the bug is triggered by the following steps
+
+1. Call btrfs_get_old_root() on the new_root.
+2. We call tree_mod_log_oldest_root(btrfs_root_node(new_root)), which is
+ currently logical 0.
+3. tree_mod_log_oldest_root() calls tree_mod_log_search_oldest(), which
+ gives us the KEY_REPLACE seq 2, and since that's not a
+ LOG_ROOT_REPLACE we incorrectly believe that we don't have an old
+ root, because we expect that the most recent change should be a
+ LOG_ROOT_REPLACE.
+4. Back in tree_mod_log_oldest_root() we don't have a LOG_ROOT_REPLACE,
+ so we don't set old_root, we simply use our existing extent buffer.
+5. Since we're using our existing extent buffer (logical 0) we call
+ tree_mod_log_search(0) in order to get the newest change to start the
+ rewind from, which ends up being the LOG_ROOT_REPLACE at seq 8.
+6. Again since we didn't find an old_root we simply clone logical 0 at
+ it's current state.
+7. We call tree_mod_log_rewind() with the cloned extent buffer.
+8. Set n = btrfs_header_nritems(logical 0), which would be whatever the
+ original nritems was when we COWed the original root, say for this
+ example it's 2.
+9. We start from the newest operation and work our way forward, so we
+ see LOG_ROOT_REPLACE which we ignore.
+10. Next we see KEY_REMOVE_WHILE_FREEING for slot 0, which triggers the
+ BUG_ON(tm->slot < n), because it expects if we've done this we have a
+ completely empty extent buffer to replay completely.
+
+The correct thing would be to find the first LOG_ROOT_REPLACE, and then
+get the old_root set to logical 8192. In fact making that change fixes
+this particular problem.
+
+However consider the much more complicated case. We have a child node
+in this tree and the above situation. In the above case we freed one
+of the child blocks at the seq 3 operation. If this block was also
+re-allocated and got new tree mod log operations we would have a
+different problem. btrfs_search_old_slot(orig root) would get down to
+the logical 0 root that still pointed at that node. However in
+btrfs_search_old_slot() we call tree_mod_log_rewind(buf) directly. This
+is not context aware enough to know which operations we should be
+replaying. If the block was re-allocated multiple times we may only
+want to replay a range of operations, and determining what that range is
+isn't possible to determine.
+
+We could maybe solve this by keeping track of which root the node
+belonged to at every tree mod log operation, and then passing this
+around to make sure we're only replaying operations that relate to the
+root we're trying to rewind.
+
+However there's a simpler way to solve this problem, simply disallow
+reallocations if we have currently running tree mod log users. We
+already do this for leaf's, so we're simply expanding this to nodes as
+well. This is a relatively uncommon occurrence, and the problem is
+complicated enough I'm worried that we will still have corner cases in
+the reallocation case. So fix this in the most straightforward way
+possible.
+
+Fixes: bd989ba359f2 ("Btrfs: add tree modification log functions")
+CC: stable@vger.kernel.org # 3.3+
+Reviewed-by: Filipe Manana <fdmanana@suse.com>
+Signed-off-by: Josef Bacik <josef@toxicpanda.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/extent-tree.c | 25 +++++++++++++------------
+ 1 file changed, 13 insertions(+), 12 deletions(-)
+
+--- a/fs/btrfs/extent-tree.c
++++ b/fs/btrfs/extent-tree.c
+@@ -3307,21 +3307,22 @@ void btrfs_free_tree_block(struct btrfs_
+ }
+
+ /*
+- * If this is a leaf and there are tree mod log users, we may
+- * have recorded mod log operations that point to this leaf.
+- * So we must make sure no one reuses this leaf's extent before
+- * mod log operations are applied to a node, otherwise after
+- * rewinding a node using the mod log operations we get an
+- * inconsistent btree, as the leaf's extent may now be used as
+- * a node or leaf for another different btree.
++ * If there are tree mod log users we may have recorded mod log
++ * operations for this node. If we re-allocate this node we
++ * could replay operations on this node that happened when it
++ * existed in a completely different root. For example if it
++ * was part of root A, then was reallocated to root B, and we
++ * are doing a btrfs_old_search_slot(root b), we could replay
++ * operations that happened when the block was part of root A,
++ * giving us an inconsistent view of the btree.
++ *
+ * We are safe from races here because at this point no other
+ * node or root points to this extent buffer, so if after this
+- * check a new tree mod log user joins, it will not be able to
+- * find a node pointing to this leaf and record operations that
+- * point to this leaf.
++ * check a new tree mod log user joins we will not have an
++ * existing log of operations on this node that we have to
++ * contend with.
+ */
+- if (btrfs_header_level(buf) == 0 &&
+- test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
++ if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
+ must_pin = true;
+
+ if (must_pin || btrfs_is_zoned(fs_info)) {
--- /dev/null
+From 2398091f9c2c8e0040f4f9928666787a3e8108a7 Mon Sep 17 00:00:00 2001
+From: David Sterba <dsterba@suse.com>
+Date: Tue, 18 Oct 2022 16:05:52 +0200
+Subject: btrfs: fix type of parameter generation in btrfs_get_dentry
+
+From: David Sterba <dsterba@suse.com>
+
+commit 2398091f9c2c8e0040f4f9928666787a3e8108a7 upstream.
+
+The type of parameter generation has been u32 since the beginning,
+however all callers pass a u64 generation, so unify the types to prevent
+potential loss.
+
+CC: stable@vger.kernel.org # 4.9+
+Reviewed-by: Josef Bacik <josef@toxicpanda.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/export.c | 2 +-
+ fs/btrfs/export.h | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+--- a/fs/btrfs/export.c
++++ b/fs/btrfs/export.c
+@@ -58,7 +58,7 @@ static int btrfs_encode_fh(struct inode
+ }
+
+ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
+- u64 root_objectid, u32 generation,
++ u64 root_objectid, u64 generation,
+ int check_generation)
+ {
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+--- a/fs/btrfs/export.h
++++ b/fs/btrfs/export.h
+@@ -19,7 +19,7 @@ struct btrfs_fid {
+ } __attribute__ ((packed));
+
+ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
+- u64 root_objectid, u32 generation,
++ u64 root_objectid, u64 generation,
+ int check_generation);
+ struct dentry *btrfs_get_parent(struct dentry *child);
+
--- /dev/null
+From 0e792b89e6800cd9cb4757a76a96f7ef3e8b6294 Mon Sep 17 00:00:00 2001
+From: Li Huafei <lihuafei1@huawei.com>
+Date: Thu, 3 Nov 2022 11:10:10 +0800
+Subject: ftrace: Fix use-after-free for dynamic ftrace_ops
+
+From: Li Huafei <lihuafei1@huawei.com>
+
+commit 0e792b89e6800cd9cb4757a76a96f7ef3e8b6294 upstream.
+
+KASAN reported a use-after-free with ftrace ops [1]. It was found from
+vmcore that perf had registered two ops with the same content
+successively, both dynamic. After unregistering the second ops, a
+use-after-free occurred.
+
+In ftrace_shutdown(), when the second ops is unregistered, the
+FTRACE_UPDATE_CALLS command is not set because there is another enabled
+ops with the same content. Also, both ops are dynamic and the ftrace
+callback function is ftrace_ops_list_func, so the
+FTRACE_UPDATE_TRACE_FUNC command will not be set. Eventually the value
+of 'command' will be 0 and ftrace_shutdown() will skip the rcu
+synchronization.
+
+However, ftrace may be activated. When the ops is released, another CPU
+may be accessing the ops. Add the missing synchronization to fix this
+problem.
+
+[1]
+BUG: KASAN: use-after-free in __ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
+BUG: KASAN: use-after-free in ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
+Read of size 8 at addr ffff56551965bbc8 by task syz-executor.2/14468
+
+CPU: 1 PID: 14468 Comm: syz-executor.2 Not tainted 5.10.0 #7
+Hardware name: linux,dummy-virt (DT)
+Call trace:
+ dump_backtrace+0x0/0x40c arch/arm64/kernel/stacktrace.c:132
+ show_stack+0x30/0x40 arch/arm64/kernel/stacktrace.c:196
+ __dump_stack lib/dump_stack.c:77 [inline]
+ dump_stack+0x1b4/0x248 lib/dump_stack.c:118
+ print_address_description.constprop.0+0x28/0x48c mm/kasan/report.c:387
+ __kasan_report mm/kasan/report.c:547 [inline]
+ kasan_report+0x118/0x210 mm/kasan/report.c:564
+ check_memory_region_inline mm/kasan/generic.c:187 [inline]
+ __asan_load8+0x98/0xc0 mm/kasan/generic.c:253
+ __ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
+ ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
+ ftrace_graph_call+0x0/0x4
+ __might_sleep+0x8/0x100 include/linux/perf_event.h:1170
+ __might_fault mm/memory.c:5183 [inline]
+ __might_fault+0x58/0x70 mm/memory.c:5171
+ do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
+ strncpy_from_user+0x1f4/0x4b0 lib/strncpy_from_user.c:139
+ getname_flags+0xb0/0x31c fs/namei.c:149
+ getname+0x2c/0x40 fs/namei.c:209
+ [...]
+
+Allocated by task 14445:
+ kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
+ kasan_set_track mm/kasan/common.c:56 [inline]
+ __kasan_kmalloc mm/kasan/common.c:479 [inline]
+ __kasan_kmalloc.constprop.0+0x110/0x13c mm/kasan/common.c:449
+ kasan_kmalloc+0xc/0x14 mm/kasan/common.c:493
+ kmem_cache_alloc_trace+0x440/0x924 mm/slub.c:2950
+ kmalloc include/linux/slab.h:563 [inline]
+ kzalloc include/linux/slab.h:675 [inline]
+ perf_event_alloc.part.0+0xb4/0x1350 kernel/events/core.c:11230
+ perf_event_alloc kernel/events/core.c:11733 [inline]
+ __do_sys_perf_event_open kernel/events/core.c:11831 [inline]
+ __se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
+ __arm64_sys_perf_event_open+0x6c/0x80 kernel/events/core.c:11723
+ [...]
+
+Freed by task 14445:
+ kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
+ kasan_set_track+0x24/0x34 mm/kasan/common.c:56
+ kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:358
+ __kasan_slab_free.part.0+0x11c/0x1b0 mm/kasan/common.c:437
+ __kasan_slab_free mm/kasan/common.c:445 [inline]
+ kasan_slab_free+0x2c/0x40 mm/kasan/common.c:446
+ slab_free_hook mm/slub.c:1569 [inline]
+ slab_free_freelist_hook mm/slub.c:1608 [inline]
+ slab_free mm/slub.c:3179 [inline]
+ kfree+0x12c/0xc10 mm/slub.c:4176
+ perf_event_alloc.part.0+0xa0c/0x1350 kernel/events/core.c:11434
+ perf_event_alloc kernel/events/core.c:11733 [inline]
+ __do_sys_perf_event_open kernel/events/core.c:11831 [inline]
+ __se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
+ [...]
+
+Link: https://lore.kernel.org/linux-trace-kernel/20221103031010.166498-1-lihuafei1@huawei.com
+
+Fixes: edb096e00724f ("ftrace: Fix memleak when unregistering dynamic ops when tracing disabled")
+Cc: stable@vger.kernel.org
+Suggested-by: Steven Rostedt <rostedt@goodmis.org>
+Signed-off-by: Li Huafei <lihuafei1@huawei.com>
+Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ kernel/trace/ftrace.c | 16 +++-------------
+ 1 file changed, 3 insertions(+), 13 deletions(-)
+
+--- a/kernel/trace/ftrace.c
++++ b/kernel/trace/ftrace.c
+@@ -2948,18 +2948,8 @@ int ftrace_shutdown(struct ftrace_ops *o
+ command |= FTRACE_UPDATE_TRACE_FUNC;
+ }
+
+- if (!command || !ftrace_enabled) {
+- /*
+- * If these are dynamic or per_cpu ops, they still
+- * need their data freed. Since, function tracing is
+- * not currently active, we can just free them
+- * without synchronizing all CPUs.
+- */
+- if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
+- goto free_ops;
+-
+- return 0;
+- }
++ if (!command || !ftrace_enabled)
++ goto out;
+
+ /*
+ * If the ops uses a trampoline, then it needs to be
+@@ -2996,6 +2986,7 @@ int ftrace_shutdown(struct ftrace_ops *o
+ removed_ops = NULL;
+ ops->flags &= ~FTRACE_OPS_FL_REMOVING;
+
++out:
+ /*
+ * Dynamic ops may be freed, we must make sure that all
+ * callers are done before leaving this function.
+@@ -3023,7 +3014,6 @@ int ftrace_shutdown(struct ftrace_ops *o
+ if (IS_ENABLED(CONFIG_PREEMPTION))
+ synchronize_rcu_tasks();
+
+- free_ops:
+ ftrace_trampoline_free(ops);
+ }
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
