From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21F114EDCCD; Thu, 17 Sep 2026 17:56:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789667782; cv=none; b=mqIUlVaRvjRIiADS2Fyi61GAT6sqmVtFV0+0sTiZxprRyGuVdNYQ6p/3fTMutxTDprBxiExT/bOxPVlWEwWYaOont+Z8cpPEE0RaddvlS3CGHiknPPX6PimiLzHzX1VK20aC+dm5yqhdXAb8zZNyrV1CKQnnitb8oHYt+ywDP70= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789667782; c=relaxed/simple; bh=c3BGrLzPOPjWgXRTAnkn6QS4J+F2wyxJ760WiugS/1Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bBvRWPKOEIDl1CJ4xDCuctYoJs4f8DMokIdsSFCNrF0CqjeuXeLg6vMhmxiq+dcHX/QGNFUqpcmf1WbCkvc+hFcxacQRcEvvIO99VVVA/8B9lRhwbOYkYcCH6CdZm0V7l7nxZqttM4jkMApKSEi3BVMyPinrZFNkVx+HipHW/yM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Xbdyeduu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Xbdyeduu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A8EB1F000FF; Thu, 17 Sep 2026 17:56:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789667781; bh=qAlacmRp+in9SI0g/kr7jMNOXINqB/WofOZvxR6t/6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XbdyeduuN9QgwixfDDcQabxktURZAJApLswy6tYC+cJd4m4gbWuMXL5Hd7P5k1Bt9 PM/0R56ibnAhiJLrtJN4iohdB69UAxzv7zkGn/tMYm9bAfkF7GgYIKxZxZ5D7dR09y SZT5IBVeRzdU5la4ZBHRX7YhBrPXLHWKUCenkrmw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Adriano Vero , Sourabh Jain , Madhavan Srinivasan , Sasha Levin Subject: [PATCH 6.12 0206/1102] powerpc/fadump: Add timeout to RTAS busy-wait loops Date: Thu, 17 Sep 2026 16:02:29 +0100 Message-ID: <20260917151544.747347292@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151539.408551884@linuxfoundation.org> References: <20260917151539.408551884@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Adriano Vero [ Upstream commit b3580dd1c68cec23d44a39c439e18b4686c13480 ] The ibm,configure-kernel-dump RTAS call sites in rtas_fadump_register(), rtas_fadump_unregister(), and rtas_fadump_invalidate() polled indefinitely while firmware returned a busy status. A misbehaving or hung firmware could stall these paths forever, blocking fadump registration at boot or preventing clean teardown. Introduce rtas_fadump_call(), a helper that wraps the common busy-wait pattern shared by all three sites. The helper accumulates the total delay and returns -ETIMEDOUT if firmware keeps returning a busy status beyond RTAS_FADUMP_MAX_WAIT_MS (60 seconds). A pr_debug() message is emitted on each busy iteration to aid diagnosis when the timeout is hit. Signed-off-by: Adriano Vero Reviewed-by: Sourabh Jain [Maddy: Fixed newline after Signed-off-by] Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260506222024.30352-1-adri.vero.dev@gmail.com Signed-off-by: Sasha Levin --- arch/powerpc/platforms/pseries/rtas-fadump.c | 80 ++++++++++++-------- arch/powerpc/platforms/pseries/rtas-fadump.h | 6 ++ 2 files changed, 53 insertions(+), 33 deletions(-) diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c index eceb3289383ec..3bb4ac2ab6cc3 100644 --- a/arch/powerpc/platforms/pseries/rtas-fadump.c +++ b/arch/powerpc/platforms/pseries/rtas-fadump.c @@ -179,9 +179,42 @@ static u64 rtas_fadump_get_bootmem_min(void) return RTAS_FADUMP_MIN_BOOT_MEM; } +/* + * Helper to make an ibm,configure-kernel-dump RTAS call with a bounded + * busy-wait loop. Returns the RTAS return code on completion, or + * -ETIMEDOUT if firmware keeps returning a busy status beyond + * RTAS_FADUMP_MAX_WAIT_MS milliseconds. + */ +static int rtas_fadump_call(struct fw_dump *fadump_conf, int operation, + void *fdm_ptr, unsigned int fdm_size, + const char *op_name) +{ + unsigned int wait_time, total_wait = 0; + int rc; + + do { + rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, + NULL, operation, fdm_ptr, fdm_size); + wait_time = rtas_busy_delay_time(rc); + if (wait_time) { + pr_debug("Firmware busy during fadump %s, waiting %ums (total %ums)\n", + op_name, wait_time, total_wait); + if (total_wait >= RTAS_FADUMP_MAX_WAIT_MS) { + pr_err("Timed out waiting for firmware to complete fadump %s\n", + op_name); + return -ETIMEDOUT; + } + total_wait += wait_time; + mdelay(wait_time); + } + } while (wait_time); + + return rc; +} + static int rtas_fadump_register(struct fw_dump *fadump_conf) { - unsigned int wait_time, fdm_size; + unsigned int fdm_size; int rc, err = -EIO; /* @@ -192,16 +225,10 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf) fdm_size = sizeof(struct rtas_fadump_section_header); fdm_size += be16_to_cpu(fdm.header.dump_num_sections) * sizeof(struct rtas_fadump_section); - /* TODO: Add upper time limit for the delay */ - do { - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, - NULL, FADUMP_REGISTER, &fdm, fdm_size); - - wait_time = rtas_busy_delay_time(rc); - if (wait_time) - mdelay(wait_time); - - } while (wait_time); + rc = rtas_fadump_call(fadump_conf, FADUMP_REGISTER, &fdm, fdm_size, + "register"); + if (rc == -ETIMEDOUT) + return -ETIMEDOUT; switch (rc) { case 0: @@ -234,19 +261,12 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf) static int rtas_fadump_unregister(struct fw_dump *fadump_conf) { - unsigned int wait_time; int rc; - /* TODO: Add upper time limit for the delay */ - do { - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, - NULL, FADUMP_UNREGISTER, &fdm, - sizeof(struct rtas_fadump_mem_struct)); - - wait_time = rtas_busy_delay_time(rc); - if (wait_time) - mdelay(wait_time); - } while (wait_time); + rc = rtas_fadump_call(fadump_conf, FADUMP_UNREGISTER, &fdm, + sizeof(struct rtas_fadump_mem_struct), "unregister"); + if (rc == -ETIMEDOUT) + return -ETIMEDOUT; if (rc) { pr_err("Failed to un-register - unexpected error(%d).\n", rc); @@ -259,19 +279,13 @@ static int rtas_fadump_unregister(struct fw_dump *fadump_conf) static int rtas_fadump_invalidate(struct fw_dump *fadump_conf) { - unsigned int wait_time; int rc; - /* TODO: Add upper time limit for the delay */ - do { - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, - NULL, FADUMP_INVALIDATE, fdm_active, - sizeof(struct rtas_fadump_mem_struct)); - - wait_time = rtas_busy_delay_time(rc); - if (wait_time) - mdelay(wait_time); - } while (wait_time); + rc = rtas_fadump_call(fadump_conf, FADUMP_INVALIDATE, + (void *)fdm_active, + sizeof(struct rtas_fadump_mem_struct), "invalidate"); + if (rc == -ETIMEDOUT) + return -ETIMEDOUT; if (rc) { pr_err("Failed to invalidate - unexpected error (%d).\n", rc); diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.h b/arch/powerpc/platforms/pseries/rtas-fadump.h index c109abf6befd9..65fdab7b5b8d3 100644 --- a/arch/powerpc/platforms/pseries/rtas-fadump.h +++ b/arch/powerpc/platforms/pseries/rtas-fadump.h @@ -41,6 +41,12 @@ #define MAX_SECTIONS 10 #define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7 +/* + * Maximum time to wait for firmware to respond to an + * ibm,configure-kernel-dump RTAS call before giving up. + */ +#define RTAS_FADUMP_MAX_WAIT_MS 60000U + /* Kernel Dump section info */ struct rtas_fadump_section { __be32 request_flag; -- 2.53.0