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Message-Id: <20180521210452.655010422@linuxfoundation.org>
Date: Mon, 21 May 2018 23:11:12 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Nicholas Piggin <npiggin@...il.com>,
Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.14 22/95] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Piggin <npiggin@...il.com>
commit c1d2a31397ec51f0370f6bd17b19b39152c263cb upstream.
Similarly to opal_event_shutdown, opal_nvram_write can be called in
the crash path with irqs disabled. Special case the delay to avoid
sleeping in invalid context.
Fixes: 3b8070335f75 ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops")
Cc: stable@...r.kernel.org # v3.2
Signed-off-by: Nicholas Piggin <npiggin@...il.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/powerpc/platforms/powernv/opal-nvram.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/arch/powerpc/platforms/powernv/opal-nvram.c
+++ b/arch/powerpc/platforms/powernv/opal-nvram.c
@@ -44,6 +44,10 @@ static ssize_t opal_nvram_read(char *buf
return count;
}
+/*
+ * This can be called in the panic path with interrupts off, so use
+ * mdelay in that case.
+ */
static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
{
s64 rc = OPAL_BUSY;
@@ -58,10 +62,16 @@ static ssize_t opal_nvram_write(char *bu
while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
rc = opal_write_nvram(__pa(buf), count, off);
if (rc == OPAL_BUSY_EVENT) {
- msleep(OPAL_BUSY_DELAY_MS);
+ if (in_interrupt() || irqs_disabled())
+ mdelay(OPAL_BUSY_DELAY_MS);
+ else
+ msleep(OPAL_BUSY_DELAY_MS);
opal_poll_events(NULL);
} else if (rc == OPAL_BUSY) {
- msleep(OPAL_BUSY_DELAY_MS);
+ if (in_interrupt() || irqs_disabled())
+ mdelay(OPAL_BUSY_DELAY_MS);
+ else
+ msleep(OPAL_BUSY_DELAY_MS);
}
}
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