64 lines
1.9 KiB
Diff
64 lines
1.9 KiB
Diff
From 658fb663bc28a42af52a216d7bf66f844dd23d69 Mon Sep 17 00:00:00 2001
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From: John Ogness <john.ogness@linutronix.de>
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Date: Fri, 20 Oct 2023 09:52:59 +0000
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Subject: [PATCH 127/196] printk: nbcon: Ensure ownership release on failed
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emit
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Until now it was assumed that ownership has been lost when the
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write_atomic() callback fails. nbcon_emit_next_record() only
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returns false when ownership has been lost.
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Ensure ownership has been lost before reporting failure by
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explicitly attempting a release. If the current context is not
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the owner, the release has no effect.
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/printk/nbcon.c | 19 ++++++++++---------
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1 file changed, 10 insertions(+), 9 deletions(-)
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diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
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index c8093bcc01fe..8ecd76aa22e6 100644
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--- a/kernel/printk/nbcon.c
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+++ b/kernel/printk/nbcon.c
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@@ -852,7 +852,7 @@ static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt)
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unsigned long con_dropped;
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struct nbcon_state cur;
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unsigned long dropped;
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- bool done;
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+ bool done = false;
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/*
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* The printk buffers are filled within an unsafe section. This
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@@ -891,17 +891,18 @@ static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt)
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nbcon_state_read(con, &cur);
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wctxt->unsafe_takeover = cur.unsafe_takeover;
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- if (con->write_atomic) {
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+ if (con->write_atomic)
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done = con->write_atomic(con, wctxt);
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- } else {
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- nbcon_context_release(ctxt);
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- WARN_ON_ONCE(1);
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- done = false;
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- }
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- /* If not done, the emit was aborted. */
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- if (!done)
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+ if (!done) {
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+ /*
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+ * The emit was aborted, probably due to a loss of ownership.
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+ * Ensure ownership was lost or released before reporting the
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+ * loss.
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+ */
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+ nbcon_context_release(ctxt);
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return false;
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+ }
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/*
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* Since any dropped message was successfully output, reset the
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--
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2.43.2
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