From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Will Deacon <will@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Hurley <peter@hurleysoftware.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 49/69] tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop
Date: Wed, 14 Aug 2019 19:01:47 +0200 [thread overview]
Message-ID: <20190814165748.892413705@linuxfoundation.org> (raw)
In-Reply-To: <20190814165744.822314328@linuxfoundation.org>
[ Upstream commit 952041a8639a7a3a73a2b6573cb8aa8518bc39f8 ]
While reviewing rwsem down_slowpath, Will noticed ldsem had a copy of
a bug we just found for rwsem.
X = 0;
CPU0 CPU1
rwsem_down_read()
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
X = 1;
rwsem_up_write();
rwsem_mark_wake()
atomic_long_add(adjustment, &sem->count);
smp_store_release(&waiter->task, NULL);
if (!waiter.task)
break;
...
}
r = X;
Allows 'r == 0'.
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4898e640caf0 ("tty: Add timed, writer-prioritized rw semaphore")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/tty_ldsem.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c
index 5c2cec298816b..c6ce34161281a 100644
--- a/drivers/tty/tty_ldsem.c
+++ b/drivers/tty/tty_ldsem.c
@@ -139,8 +139,7 @@ static void __ldsem_wake_readers(struct ld_semaphore *sem)
list_for_each_entry_safe(waiter, next, &sem->read_wait, list) {
tsk = waiter->task;
- smp_mb();
- waiter->task = NULL;
+ smp_store_release(&waiter->task, NULL);
wake_up_process(tsk);
put_task_struct(tsk);
}
@@ -235,7 +234,7 @@ down_read_failed(struct ld_semaphore *sem, long count, long timeout)
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
- if (!waiter.task)
+ if (!smp_load_acquire(&waiter.task))
break;
if (!timeout)
break;
--
2.20.1
next prev parent reply other threads:[~2019-08-14 17:15 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 17:00 [PATCH 4.14 00/69] 4.14.139-stable review Greg Kroah-Hartman
2019-08-14 17:00 ` [PATCH 4.14 01/69] iio: adc: max9611: Fix misuse of GENMASK macro Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 02/69] crypto: ccp - Fix oops by properly managing allocated structures Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 03/69] crypto: ccp - Ignore tag length when decrypting GCM ciphertext Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 04/69] usb: usbfs: fix double-free of usb memory upon submiturb error Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 05/69] usb: iowarrior: fix deadlock on disconnect Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 06/69] sound: fix a memory leak bug Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 07/69] mmc: cavium: Set the correct dma max segment size for mmc_host Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 08/69] mmc: cavium: Add the missing dma unmap when the dma has finished Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 09/69] loop: set PF_MEMALLOC_NOIO for the worker thread Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 10/69] Input: synaptics - enable RMI mode for HP Spectre X360 Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 11/69] lkdtm: support llvm-objcopy Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 12/69] crypto: ccp - Validate buffer lengths for copy operations Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 13/69] crypto: ccp - Add support for valid authsize values less than 16 Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 14/69] tcp: Clear sk_send_head after purging the write queue Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 15/69] x86/mm: Check for pfn instead of page in vmalloc_sync_one() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 16/69] x86/mm: Sync also unmappings in vmalloc_sync_all() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 17/69] mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 18/69] perf annotate: Fix s390 gap between kernel end and module start Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 19/69] perf db-export: Fix thread__exec_comm() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 20/69] perf record: Fix module size on s390 Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 21/69] usb: host: xhci-rcar: Fix timeout in xhci_suspend() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 22/69] usb: yurex: Fix use-after-free in yurex_delete Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 23/69] can: rcar_canfd: fix possible IRQ storm on high load Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 24/69] can: peak_usb: fix potential double kfree_skb() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 25/69] netfilter: nfnetlink: avoid deadlock due to synchronous request_module Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 26/69] vfio-ccw: Set pa_nr to 0 if memory allocation fails for pa_iova_pfn Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 27/69] netfilter: Fix rpfilter dropping vrf packets by mistake Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 28/69] netfilter: nft_hash: fix symhash with modulus one Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 29/69] scripts/sphinx-pre-install: fix script for RHEL/CentOS Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 30/69] iscsi_ibft: make ISCSI_IBFT dependson ACPI instead of ISCSI_IBFT_FIND Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 31/69] mac80211: dont warn about CW params when not using them Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 32/69] hwmon: (nct6775) Fix register address and added missed tolerance for nct6106 Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 33/69] drm: silence variable conn set but not used Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 34/69] cpufreq/pasemi: fix use-after-free in pas_cpufreq_cpu_init() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 35/69] s390/qdio: add sanity checks to the fast-requeue path Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 36/69] ALSA: compress: Fix regression on compressed capture streams Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 37/69] ALSA: compress: Prevent bypasses of set_params Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 38/69] ALSA: compress: Dont allow paritial drain operations on capture streams Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 39/69] ALSA: compress: Be more restrictive about when a drain is allowed Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 40/69] perf tools: Fix proper buffer size for feature processing Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 41/69] perf probe: Avoid calling freeing routine multiple times for same pointer Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 42/69] drbd: dynamically allocate shash descriptor Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 43/69] ACPI/IORT: Fix off-by-one check in iort_dev_find_its_id() Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 44/69] ARM: davinci: fix sleep.S build error on ARMv4 Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 45/69] scsi: megaraid_sas: fix panic on loading firmware crashdump Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 46/69] scsi: ibmvfc: fix WARN_ON during event pool release Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 47/69] scsi: scsi_dh_alua: always use a 2 second delay before retrying RTPG Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 48/69] test_firmware: fix a memory leak bug Greg Kroah-Hartman
2019-08-14 17:01 ` Greg Kroah-Hartman [this message]
2019-08-14 17:01 ` [PATCH 4.14 50/69] perf/core: Fix creating kernel counters for PMUs that override event->cpu Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 51/69] HID: sony: Fix race condition between rumble and device remove Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 52/69] can: peak_usb: pcan_usb_pro: Fix info-leaks to USB devices Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 53/69] can: peak_usb: pcan_usb_fd: " Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 54/69] hwmon: (nct7802) Fix wrong detection of in4 presence Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 55/69] drm/i915: Fix wrong escape clock divisor init for GLK Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 56/69] ALSA: firewire: fix a memory leak bug Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 57/69] ALSA: hda - Dont override global PCM hw info flag Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 58/69] ALSA: hda - Workaround for crackled sound on AMD controller (1022:1457) Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 59/69] mac80211: dont WARN on short WMM parameters from AP Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 60/69] SMB3: Fix deadlock in validate negotiate hits reconnect Greg Kroah-Hartman
2019-08-14 17:01 ` [PATCH 4.14 61/69] smb3: send CAP_DFS capability during session setup Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 62/69] NFSv4: Only pass the delegation to setattr if were sending a truncate Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 63/69] NFSv4: Fix an Oops in nfs4_do_setattr Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 64/69] KVM: Fix leak vCPUs VMCS value into other pCPU Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 65/69] mwifiex: fix 802.11n/WPA detection Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 66/69] iwlwifi: dont unmap as page memory that was mapped as single Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 67/69] iwlwifi: mvm: fix an out-of-bound access Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 68/69] iwlwifi: mvm: dont send GEO_TX_POWER_LIMIT on version < 41 Greg Kroah-Hartman
2019-08-14 17:02 ` [PATCH 4.14 69/69] iwlwifi: mvm: fix version check for GEO_TX_POWER_LIMIT support Greg Kroah-Hartman
2019-08-14 22:56 ` [PATCH 4.14 00/69] 4.14.139-stable review kernelci.org bot
2019-08-15 1:20 ` Naresh Kamboju
2019-08-15 15:17 ` Guenter Roeck
2019-08-16 2:37 ` shuah
2019-08-16 7:15 ` Greg Kroah-Hartman
2019-08-16 6:37 ` Kelsey Skunberg
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