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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2023-08-30 10:04:04 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2023-09-06 10:39:31 +0200
commit7645629f7dc88cd777f98970134bf1a54c8d77e3 (patch)
treedde5b29cdd03e8b33e1e902e4b7d1f538786d17b /kernel
parenta454d84ee20baf7bd7be90721b9821f73c7d23d9 (diff)
bpf: Invoke __bpf_prog_exit_sleepable_recur() on recursion in kern_sys_bpf().
If __bpf_prog_enter_sleepable_recur() detects recursion then it returns 0 without undoing rcu_read_lock_trace(), migrate_disable() or decrementing the recursion counter. This is fine in the JIT case because the JIT code will jump in the 0 case to the end and invoke the matching exit trampoline (__bpf_prog_exit_sleepable_recur()). This is not the case in kern_sys_bpf() which returns directly to the caller with an error code. Add __bpf_prog_exit_sleepable_recur() as clean up in the recursion case. Fixes: b1d18a7574d0d ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20230830080405.251926-2-bigeasy@linutronix.de
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/syscall.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ebeb0695305a..53a0b62464e9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5505,6 +5505,7 @@ int kern_sys_bpf(int cmd, union bpf_attr *attr, unsigned int size)
run_ctx.saved_run_ctx = NULL;
if (!__bpf_prog_enter_sleepable_recur(prog, &run_ctx)) {
/* recursion detected */
+ __bpf_prog_exit_sleepable_recur(prog, 0, &run_ctx);
bpf_prog_put(prog);
return -EBUSY;
}