From: KaFai Wan <kafai.wan@linux.dev> stable inclusion from stable-v6.6.113 commit b6e9645be9eb93f7aff3ca887f8edb6f1d63358f category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID8BLB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ---------------------------------------------------------------------- [ Upstream commit 4f375ade6aa9f37fd72d7a78682f639772089eed ] When unpinning a BPF hash table (htab or htab_lru) that contains internal structures (timer, workqueue, or task_work) in its values, a BUG warning is triggered: BUG: sleeping function called from invalid context at kernel/bpf/hashtab.c:244 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 14, name: ksoftirqd/0 ... The issue arises from the interaction between BPF object unpinning and RCU callback mechanisms: 1. BPF object unpinning uses ->free_inode() which schedules cleanup via call_rcu(), deferring the actual freeing to an RCU callback that executes within the RCU_SOFTIRQ context. 2. During cleanup of hash tables containing internal structures, htab_map_free_internal_structs() is invoked, which includes cond_resched() or cond_resched_rcu() calls to yield the CPU during potentially long operations. However, cond_resched() or cond_resched_rcu() cannot be safely called from atomic RCU softirq context, leading to the BUG warning when attempting to reschedule. Fix this by changing from ->free_inode() to ->destroy_inode() and rename bpf_free_inode() to bpf_destroy_inode() for BPF objects (prog, map, link). This allows direct inode freeing without RCU callback scheduling, avoiding the invalid context warning. Reported-by: Le Chen <tom2cat@sjtu.edu.cn> Closes: https://lore.kernel.org/all/1444123482.1827743.1750996347470.JavaMail.zimbra... Fixes: 68134668c17f ("bpf: Add map side support for bpf timers.") Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: KaFai Wan <kafai.wan@linux.dev> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20251008102628.808045-2-kafai.wan@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- kernel/bpf/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 99d0625b6c82..9a9630adcba4 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -607,7 +607,7 @@ static int bpf_show_options(struct seq_file *m, struct dentry *root) return 0; } -static void bpf_free_inode(struct inode *inode) +static void bpf_destroy_inode(struct inode *inode) { enum bpf_type type; @@ -622,7 +622,7 @@ static const struct super_operations bpf_super_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, .show_options = bpf_show_options, - .free_inode = bpf_free_inode, + .destroy_inode = bpf_destroy_inode, }; enum { -- 2.34.1