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| author | Florian Westphal <fw@strlen.de> | 2024-10-07 22:52:24 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-10-17 00:28:07 -0700 |
| commit | dc783ba4b9df3fb3e76e968b2cbeb9960069263c (patch) | |
| tree | 78f5621308fbdb7f8f0fa3d32784ddf4bc85dd43 | |
| parent | 6fa1066fc5d00cb9f1b0e83b7ff6ef98d26ba2aa (diff) | |
| download | linux-dc783ba4b9df3fb3e76e968b2cbeb9960069263c.tar.gz linux-dc783ba4b9df3fb3e76e968b2cbeb9960069263c.tar.bz2 linux-dc783ba4b9df3fb3e76e968b2cbeb9960069263c.zip | |
lib: alloc_tag_module_unload must wait for pending kfree_rcu calls
Ben Greear reports following splat:
------------[ cut here ]------------
net/netfilter/nf_nat_core.c:1114 module nf_nat func:nf_nat_register_fn has 256 allocated at module unload
WARNING: CPU: 1 PID: 10421 at lib/alloc_tag.c:168 alloc_tag_module_unload+0x22b/0x3f0
Modules linked in: nf_nat(-) btrfs ufs qnx4 hfsplus hfs minix vfat msdos fat
...
Hardware name: Default string Default string/SKYBAY, BIOS 5.12 08/04/2020
RIP: 0010:alloc_tag_module_unload+0x22b/0x3f0
codetag_unload_module+0x19b/0x2a0
? codetag_load_module+0x80/0x80
nf_nat module exit calls kfree_rcu on those addresses, but the free
operation is likely still pending by the time alloc_tag checks for leaks.
Wait for outstanding kfree_rcu operations to complete before checking
resolves this warning.
Reproducer:
unshare -n iptables-nft -t nat -A PREROUTING -p tcp
grep nf_nat /proc/allocinfo # will list 4 allocations
rmmod nft_chain_nat
rmmod nf_nat # will WARN.
[akpm@linux-foundation.org: add comment]
Link: https://lkml.kernel.org/r/20241007205236.11847-1-fw@strlen.de
Fixes: a473573964e5 ("lib: code tagging module support")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reported-by: Ben Greear <greearb@candelatech.com>
Closes: https://lore.kernel.org/netdev/bdaaef9d-4364-4171-b82b-bcfc12e207eb@candelatech.com/
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | lib/codetag.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/codetag.c b/lib/codetag.c index afa8a2d4f317..d1fbbb7c2ec3 100644 --- a/lib/codetag.c +++ b/lib/codetag.c @@ -228,6 +228,9 @@ bool codetag_unload_module(struct module *mod) if (!mod) return true; + /* await any module's kfree_rcu() operations to complete */ + kvfree_rcu_barrier(); + mutex_lock(&codetag_lock); list_for_each_entry(cttype, &codetag_types, link) { struct codetag_module *found = NULL; |