From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
Mike Christie <michael.christie@oracle.com>,
Lee Duncan <lduncan@suse.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 18/42] scsi: libiscsi: Fix NOP race condition
Date: Tue, 1 Dec 2020 09:53:16 +0100 [thread overview]
Message-ID: <20201201084643.372582131@linuxfoundation.org> (raw)
In-Reply-To: <20201201084642.194933793@linuxfoundation.org>
From: Lee Duncan <lduncan@suse.com>
[ Upstream commit fe0a8a95e7134d0b44cd407bc0085b9ba8d8fe31 ]
iSCSI NOPs are sometimes "lost", mistakenly sent to the user-land iscsid
daemon instead of handled in the kernel, as they should be, resulting in a
message from the daemon like:
iscsid: Got nop in, but kernel supports nop handling.
This can occur because of the new forward- and back-locks, and the fact
that an iSCSI NOP response can occur before processing of the NOP send is
complete. This can result in "conn->ping_task" being NULL in
iscsi_nop_out_rsp(), when the pointer is actually in the process of being
set.
To work around this, we add a new state to the "ping_task" pointer. In
addition to NULL (not assigned) and a pointer (assigned), we add the state
"being set", which is signaled with an INVALID pointer (using "-1").
Link: https://lore.kernel.org/r/20201106193317.16993-1-leeman.duncan@gmail.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/libiscsi.c | 23 +++++++++++++++--------
include/scsi/libiscsi.h | 3 +++
2 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index c4336b01db23c..a84b473d4a08b 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -570,8 +570,8 @@ static void iscsi_complete_task(struct iscsi_task *task, int state)
if (conn->task == task)
conn->task = NULL;
- if (conn->ping_task == task)
- conn->ping_task = NULL;
+ if (READ_ONCE(conn->ping_task) == task)
+ WRITE_ONCE(conn->ping_task, NULL);
/* release get from queueing */
__iscsi_put_task(task);
@@ -780,6 +780,9 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
task->conn->session->age);
}
+ if (unlikely(READ_ONCE(conn->ping_task) == INVALID_SCSI_TASK))
+ WRITE_ONCE(conn->ping_task, task);
+
if (!ihost->workq) {
if (iscsi_prep_mgmt_task(conn, task))
goto free_task;
@@ -987,8 +990,11 @@ static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
struct iscsi_nopout hdr;
struct iscsi_task *task;
- if (!rhdr && conn->ping_task)
- return -EINVAL;
+ if (!rhdr) {
+ if (READ_ONCE(conn->ping_task))
+ return -EINVAL;
+ WRITE_ONCE(conn->ping_task, INVALID_SCSI_TASK);
+ }
memset(&hdr, 0, sizeof(struct iscsi_nopout));
hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
@@ -1003,11 +1009,12 @@ static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
if (!task) {
+ if (!rhdr)
+ WRITE_ONCE(conn->ping_task, NULL);
iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
return -EIO;
} else if (!rhdr) {
/* only track our nops */
- conn->ping_task = task;
conn->last_ping = jiffies;
}
@@ -1020,7 +1027,7 @@ static int iscsi_nop_out_rsp(struct iscsi_task *task,
struct iscsi_conn *conn = task->conn;
int rc = 0;
- if (conn->ping_task != task) {
+ if (READ_ONCE(conn->ping_task) != task) {
/*
* If this is not in response to one of our
* nops then it must be from userspace.
@@ -1960,7 +1967,7 @@ static void iscsi_start_tx(struct iscsi_conn *conn)
*/
static int iscsi_has_ping_timed_out(struct iscsi_conn *conn)
{
- if (conn->ping_task &&
+ if (READ_ONCE(conn->ping_task) &&
time_before_eq(conn->last_recv + (conn->recv_timeout * HZ) +
(conn->ping_timeout * HZ), jiffies))
return 1;
@@ -2095,7 +2102,7 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
* Checking the transport already or nop from a cmd timeout still
* running
*/
- if (conn->ping_task) {
+ if (READ_ONCE(conn->ping_task)) {
task->have_checked_conn = true;
rc = BLK_EH_RESET_TIMER;
goto done;
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index c7b1dc713cdd7..9c7f4aad6db66 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -144,6 +144,9 @@ struct iscsi_task {
void *dd_data; /* driver/transport data */
};
+/* invalid scsi_task pointer */
+#define INVALID_SCSI_TASK (struct iscsi_task *)-1l
+
static inline int iscsi_task_has_unsol_data(struct iscsi_task *task)
{
return task->unsol_r2t.data_length > task->unsol_r2t.sent;
--
2.27.0
next prev parent reply other threads:[~2020-12-01 8:55 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 8:52 [PATCH 4.9 00/42] 4.9.247-rc1 review Greg Kroah-Hartman
2020-12-01 8:52 ` [PATCH 4.9 01/42] perf event: Check ref_reloc_sym before using it Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 02/42] mm/userfaultfd: do not access vma->vm_mm after calling handle_userfault() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 03/42] btrfs: fix lockdep splat when reading qgroup config on mount Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 04/42] PCI: Add device even if driver attach failed Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 05/42] btrfs: tree-checker: Enhance chunk checker to validate chunk profile Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 06/42] btrfs: inode: Verify inode mode to avoid NULL pointer dereference Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 07/42] KVM: x86: Fix split-irqchip vs interrupt injection window request Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 08/42] arm64: pgtable: Fix pte_accessible() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 09/42] ALSA: hda/hdmi: Use single mutex unlock in error paths Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 10/42] ALSA: hda/hdmi: fix incorrect locking in hdmi_pcm_close Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 11/42] HID: cypress: Support Varmilo Keyboards media hotkeys Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 12/42] Input: i8042 - allow insmod to succeed on devices without an i8042 controller Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 13/42] HID: hid-sensor-hub: Fix issue with devices with no report ID Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 14/42] dmaengine: xilinx_dma: use readl_poll_timeout_atomic variant Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 15/42] x86/xen: dont unbind uninitialized lock_kicker_irq Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 16/42] proc: dont allow async path resolution of /proc/self components Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 17/42] dmaengine: pl330: _prep_dma_memcpy: Fix wrong burst size Greg Kroah-Hartman
2020-12-01 8:53 ` Greg Kroah-Hartman [this message]
2020-12-01 8:53 ` [PATCH 4.9 19/42] scsi: target: iscsi: Fix cmd abort fabric stop race Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 20/42] perf/x86: fix sysfs type mismatches Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 21/42] phy: tegra: xusb: Fix dangling pointer on probe failure Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 22/42] batman-adv: set .owner to THIS_MODULE Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 23/42] scsi: ufs: Fix race between shutdown and runtime resume flow Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 24/42] bnxt_en: fix error return code in bnxt_init_board() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 25/42] video: hyperv_fb: Fix the cache type when mapping the VRAM Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 26/42] bnxt_en: Release PCI regions when DMA mask setup fails during probe Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 27/42] IB/mthca: fix return value of error branch in mthca_init_cq() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 28/42] nfc: s3fwrn5: use signed integer for parsing GPIO numbers Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 29/42] net: ena: set initial DMA width to avoid intel iommu issue Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 30/42] ibmvnic: fix NULL pointer dereference in ibmvic_reset_crq Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 31/42] efivarfs: revert "fix memory leak in efivarfs_create()" Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 32/42] can: gs_usb: fix endianess problem with candleLight firmware Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 33/42] platform/x86: toshiba_acpi: Fix the wrong variable assignment Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 34/42] perf probe: Fix to die_entrypc() returns error correctly Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 35/42] USB: core: Change %pK for __user pointers to %px Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 36/42] usb: gadget: f_midi: Fix memleak in f_midi_alloc Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 37/42] usb: gadget: Fix memleak in gadgetfs_fill_super Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 38/42] x86/speculation: Fix prctl() when spectre_v2_user={seccomp,prctl},ibpb Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 39/42] regulator: avoid resolve_supply() infinite recursion Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 40/42] regulator: workaround self-referent regulators Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 41/42] USB: core: add endpoint-blacklist quirk Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 42/42] USB: core: Fix regression in Hercules audio card Greg Kroah-Hartman
2020-12-01 21:39 ` [PATCH 4.9 00/42] 4.9.247-rc1 review Guenter Roeck
2020-12-02 6:14 ` Naresh Kamboju
2020-12-02 17:04 ` Shuah Khan
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