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Patch "scsi: libsas: fix memory leak in sas_smp_get_phy_events()" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled scsi: libsas: fix memory leak in sas_smp_get_phy_events() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: scsi-libsas-fix-memory-leak-in-sas_smp_get_phy_events.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Jason Yan <yanaijie(a)huawei.com> Date: Thu, 4 Jan 2018 21:04:31 +0800 Subject: scsi: libsas: fix memory leak in sas_smp_get_phy_events() From: Jason Yan <yanaijie(a)huawei.com> [ Upstream commit 4a491b1ab11ca0556d2fda1ff1301e862a2d44c4 ] We've got a memory leak with the following producer: while true; do cat /sys/class/sas_phy/phy-1:0:12/invalid_dword_count >/dev/null; done The buffer req is allocated and not freed after we return. Fix it. Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") Signed-off-by: Jason Yan <yanaijie(a)huawei.com> CC: John Garry <john.garry(a)huawei.com> CC: chenqilin <chenqilin2(a)huawei.com> CC: chenxiang <chenxiang66(a)hisilicon.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Reviewed-by: Hannes Reinecke <hare(a)suse.com> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/scsi/libsas/sas_expander.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -684,6 +684,7 @@ int sas_smp_get_phy_events(struct sas_ph phy->phy_reset_problem_count = scsi_to_u32(&resp[24]); out: + kfree(req); kfree(resp); return res; Patches currently in stable-queue which might be from yanaijie(a)huawei.com are queue-4.9/scsi-libsas-initialize-sas_phy-status-according-to-response-of-discover.patch queue-4.9/scsi-libsas-fix-error-when-getting-phy-events.patch queue-4.9/scsi-libsas-fix-memory-leak-in-sas_smp_get_phy_events.patch

7 years, 6 months

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Patch "scsi: libiscsi: Allow sd_shutdown on bad transport" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled scsi: libiscsi: Allow sd_shutdown on bad transport to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: scsi-libiscsi-allow-sd_shutdown-on-bad-transport.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Rafael David Tinoco <rafael.tinoco(a)canonical.com> Date: Thu, 7 Dec 2017 19:59:13 -0200 Subject: scsi: libiscsi: Allow sd_shutdown on bad transport From: Rafael David Tinoco <rafael.tinoco(a)canonical.com> [ Upstream commit d754941225a7dbc61f6dd2173fa9498049f9a7ee ] If, for any reason, userland shuts down iscsi transport interfaces before proper logouts - like when logging in to LUNs manually, without logging out on server shutdown, or when automated scripts can't umount/logout from logged LUNs - kernel will hang forever on its sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all still existent paths. PID: 1 TASK: ffff8801a69b8000 CPU: 1 COMMAND: "systemd-shutdow" #0 [ffff8801a69c3a30] __schedule at ffffffff8183e9ee #1 [ffff8801a69c3a80] schedule at ffffffff8183f0d5 #2 [ffff8801a69c3a98] schedule_timeout at ffffffff81842199 #3 [ffff8801a69c3b40] io_schedule_timeout at ffffffff8183e604 #4 [ffff8801a69c3b70] wait_for_completion_io_timeout at ffffffff8183fc6c #5 [ffff8801a69c3bd0] blk_execute_rq at ffffffff813cfe10 #6 [ffff8801a69c3c88] scsi_execute at ffffffff815c3fc7 #7 [ffff8801a69c3cc8] scsi_execute_req_flags at ffffffff815c60fe #8 [ffff8801a69c3d30] sd_sync_cache at ffffffff815d37d7 #9 [ffff8801a69c3da8] sd_shutdown at ffffffff815d3c3c This happens because iscsi_eh_cmd_timed_out(), the transport layer timeout helper, would tell the queue timeout function (scsi_times_out) to reset the request timer over and over, until the session state is back to logged in state. Unfortunately, during server shutdown, this might never happen again. Other option would be "not to handle" the issue in the transport layer. That would trigger the error handler logic, which would also need the session state to be logged in again. Best option, for such case, is to tell upper layers that the command was handled during the transport layer error handler helper, marking it as DID_NO_CONNECT, which will allow completion and inform about the problem. After the session was marked as ISCSI_STATE_FAILED, due to the first timeout during the server shutdown phase, all subsequent cmds will fail to be queued, allowing upper logic to fail faster. Signed-off-by: Rafael David Tinoco <rafael.tinoco(a)canonical.com> Reviewed-by: Lee Duncan <lduncan(a)suse.com> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/scsi/libiscsi.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -1695,6 +1695,15 @@ int iscsi_queuecommand(struct Scsi_Host */ switch (session->state) { case ISCSI_STATE_FAILED: + /* + * cmds should fail during shutdown, if the session + * state is bad, allowing completion to happen + */ + if (unlikely(system_state != SYSTEM_RUNNING)) { + reason = FAILURE_SESSION_FAILED; + sc->result = DID_NO_CONNECT << 16; + break; + } case ISCSI_STATE_IN_RECOVERY: reason = FAILURE_SESSION_IN_RECOVERY; sc->result = DID_IMM_RETRY << 16; @@ -1980,6 +1989,19 @@ static enum blk_eh_timer_return iscsi_eh if (session->state != ISCSI_STATE_LOGGED_IN) { /* + * During shutdown, if session is prematurely disconnected, + * recovery won't happen and there will be hung cmds. Not + * handling cmds would trigger EH, also bad in this case. + * Instead, handle cmd, allow completion to happen and let + * upper layer to deal with the result. + */ + if (unlikely(system_state != SYSTEM_RUNNING)) { + sc->result = DID_NO_CONNECT << 16; + ISCSI_DBG_EH(session, "sc on shutdown, handled\n"); + rc = BLK_EH_HANDLED; + goto done; + } + /* * We are probably in the middle of iscsi recovery so let * that complete and handle the error. */ @@ -2083,7 +2105,7 @@ done: task->last_timeout = jiffies; spin_unlock(&session->frwd_lock); ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ? - "timer reset" : "nh"); + "timer reset" : "shutdown or nh"); return rc; } Patches currently in stable-queue which might be from rafael.tinoco(a)canonical.com are queue-4.9/scsi-libiscsi-allow-sd_shutdown-on-bad-transport.patch

7 years, 6 months

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Patch "scsi: libsas: fix error when getting phy events" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled scsi: libsas: fix error when getting phy events to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: scsi-libsas-fix-error-when-getting-phy-events.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Jason Yan <yanaijie(a)huawei.com> Date: Thu, 4 Jan 2018 21:04:32 +0800 Subject: scsi: libsas: fix error when getting phy events From: Jason Yan <yanaijie(a)huawei.com> [ Upstream commit 2b23d9509fd7174b362482cf5f3b5f9a2265bc33 ] The intend purpose here was to goto out if smp_execute_task() returned error. Obviously something got screwed up. We will never get these link error statistics below: ~:/sys/class/sas_phy/phy-1:0:12 # cat invalid_dword_count 0 ~:/sys/class/sas_phy/phy-1:0:12 # cat running_disparity_error_count 0 ~:/sys/class/sas_phy/phy-1:0:12 # cat loss_of_dword_sync_count 0 ~:/sys/class/sas_phy/phy-1:0:12 # cat phy_reset_problem_count 0 Obviously we should goto error handler if smp_execute_task() returns non-zero. Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") Signed-off-by: Jason Yan <yanaijie(a)huawei.com> CC: John Garry <john.garry(a)huawei.com> CC: chenqilin <chenqilin2(a)huawei.com> CC: chenxiang <chenxiang66(a)hisilicon.com> Reviewed-by: Hannes Reinecke <hare(a)suse.com> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/scsi/libsas/sas_expander.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -675,7 +675,7 @@ int sas_smp_get_phy_events(struct sas_ph res = smp_execute_task(dev, req, RPEL_REQ_SIZE, resp, RPEL_RESP_SIZE); - if (!res) + if (res) goto out; phy->invalid_dword_count = scsi_to_u32(&resp[12]); Patches currently in stable-queue which might be from yanaijie(a)huawei.com are queue-4.9/scsi-libsas-initialize-sas_phy-status-according-to-response-of-discover.patch queue-4.9/scsi-libsas-fix-error-when-getting-phy-events.patch queue-4.9/scsi-libsas-fix-memory-leak-in-sas_smp_get_phy_events.patch

7 years, 6 months

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Patch "scsi: bnx2fc: fix race condition in bnx2fc_get_host_stats()" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled scsi: bnx2fc: fix race condition in bnx2fc_get_host_stats() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: scsi-bnx2fc-fix-race-condition-in-bnx2fc_get_host_stats.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Maurizio Lombardi <mlombard(a)redhat.com> Date: Wed, 24 May 2017 14:09:44 +0200 Subject: scsi: bnx2fc: fix race condition in bnx2fc_get_host_stats() From: Maurizio Lombardi <mlombard(a)redhat.com> [ Upstream commit c2dd893a3b0772d1c680e109b9d5715d7f73022b ] If multiple tasks attempt to read the stats, it may happen that the start_req_done completion is re-initialized while still being used by another task, causing a list corruption. This patch fixes the bug by adding a mutex to serialize the calls to bnx2fc_get_host_stats(). WARNING: at lib/list_debug.c:48 list_del+0x6e/0xa0() (Not tainted) Hardware name: PowerEdge R820 list_del corruption. prev->next should be ffff882035627d90, but was ffff884069541588 Pid: 40267, comm: perl Not tainted 2.6.32-642.3.1.el6.x86_64 #1 Call Trace: [<ffffffff8107c691>] ? warn_slowpath_common+0x91/0xe0 [<ffffffff8107c796>] ? warn_slowpath_fmt+0x46/0x60 [<ffffffff812ad16e>] ? list_del+0x6e/0xa0 [<ffffffff81547eed>] ? wait_for_common+0x14d/0x180 [<ffffffff8106c4a0>] ? default_wake_function+0x0/0x20 [<ffffffff81547fd3>] ? wait_for_completion_timeout+0x13/0x20 [<ffffffffa05410b1>] ? bnx2fc_get_host_stats+0xa1/0x280 [bnx2fc] [<ffffffffa04cf630>] ? fc_stat_show+0x90/0xc0 [scsi_transport_fc] [<ffffffffa04cf8b6>] ? show_fcstat_tx_frames+0x16/0x20 [scsi_transport_fc] [<ffffffff8137c647>] ? dev_attr_show+0x27/0x50 [<ffffffff8113b9be>] ? __get_free_pages+0xe/0x50 [<ffffffff812170e1>] ? sysfs_read_file+0x111/0x200 [<ffffffff8119a305>] ? vfs_read+0xb5/0x1a0 [<ffffffff8119b0b6>] ? fget_light_pos+0x16/0x50 [<ffffffff8119a651>] ? sys_read+0x51/0xb0 [<ffffffff810ee1fe>] ? __audit_syscall_exit+0x25e/0x290 [<ffffffff8100b0d2>] ? system_call_fastpath+0x16/0x1b Signed-off-by: Maurizio Lombardi <mlombard(a)redhat.com> Acked-by: Chad Dupuis <chad.dupuis(a)cavium.com> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/scsi/bnx2fc/bnx2fc.h | 1 + drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) --- a/drivers/scsi/bnx2fc/bnx2fc.h +++ b/drivers/scsi/bnx2fc/bnx2fc.h @@ -191,6 +191,7 @@ struct bnx2fc_hba { struct bnx2fc_cmd_mgr *cmd_mgr; spinlock_t hba_lock; struct mutex hba_mutex; + struct mutex hba_stats_mutex; unsigned long adapter_state; #define ADAPTER_STATE_UP 0 #define ADAPTER_STATE_GOING_DOWN 1 --- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c +++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c @@ -670,15 +670,17 @@ static struct fc_host_statistics *bnx2fc if (!fw_stats) return NULL; + mutex_lock(&hba->hba_stats_mutex); + bnx2fc_stats = fc_get_host_stats(shost); init_completion(&hba->stat_req_done); if (bnx2fc_send_stat_req(hba)) - return bnx2fc_stats; + goto unlock_stats_mutex; rc = wait_for_completion_timeout(&hba->stat_req_done, (2 * HZ)); if (!rc) { BNX2FC_HBA_DBG(lport, "FW stat req timed out\n"); - return bnx2fc_stats; + goto unlock_stats_mutex; } BNX2FC_STATS(hba, rx_stat2, fc_crc_cnt); bnx2fc_stats->invalid_crc_count += hba->bfw_stats.fc_crc_cnt; @@ -700,6 +702,9 @@ static struct fc_host_statistics *bnx2fc memcpy(&hba->prev_stats, hba->stats_buffer, sizeof(struct fcoe_statistics_params)); + +unlock_stats_mutex: + mutex_unlock(&hba->hba_stats_mutex); return bnx2fc_stats; } @@ -1348,6 +1353,7 @@ static struct bnx2fc_hba *bnx2fc_hba_cre } spin_lock_init(&hba->hba_lock); mutex_init(&hba->hba_mutex); + mutex_init(&hba->hba_stats_mutex); hba->cnic = cnic; Patches currently in stable-queue which might be from mlombard(a)redhat.com are queue-4.9/scsi-bnx2fc-fix-race-condition-in-bnx2fc_get_host_stats.patch

7 years, 6 months

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Patch "scsi: csiostor: fix use after free in csio_hw_use_fwconfig()" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled scsi: csiostor: fix use after free in csio_hw_use_fwconfig() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: scsi-csiostor-fix-use-after-free-in-csio_hw_use_fwconfig.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Varun Prakash <varun(a)chelsio.com> Date: Wed, 17 May 2017 20:30:43 +0530 Subject: scsi: csiostor: fix use after free in csio_hw_use_fwconfig() From: Varun Prakash <varun(a)chelsio.com> [ Upstream commit a351e40b6de550049423a26f7ded7b639e363d89 ] mbp pointer is passed to csio_hw_validate_caps() so call mempool_free() after calling csio_hw_validate_caps(). Signed-off-by: Varun Prakash <varun(a)chelsio.com> Fixes: 541c571fa2fd ("csiostor:Use firmware version from cxgb4/t4fw_version.h") Reviewed-by: Johannes Thumshirn <jthumshirn(a)suse.de> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/scsi/csiostor/csio_hw.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/scsi/csiostor/csio_hw.c +++ b/drivers/scsi/csiostor/csio_hw.c @@ -1769,7 +1769,6 @@ csio_hw_use_fwconfig(struct csio_hw *hw, goto bye; } - mempool_free(mbp, hw->mb_mempool); if (finicsum != cfcsum) { csio_warn(hw, "Config File checksum mismatch: csum=%#x, computed=%#x\n", @@ -1780,6 +1779,10 @@ csio_hw_use_fwconfig(struct csio_hw *hw, rv = csio_hw_validate_caps(hw, mbp); if (rv != 0) goto bye; + + mempool_free(mbp, hw->mb_mempool); + mbp = NULL; + /* * Note that we're operating with parameters * not supplied by the driver, rather than from hard-wired Patches currently in stable-queue which might be from varun(a)chelsio.com are queue-4.9/scsi-csiostor-fix-use-after-free-in-csio_hw_use_fwconfig.patch

7 years, 6 months

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Patch "sched/numa: Use down_read_trylock() for the mmap_sem" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled sched/numa: Use down_read_trylock() for the mmap_sem to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: sched-numa-use-down_read_trylock-for-the-mmap_sem.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Vlastimil Babka <vbabka(a)suse.cz> Date: Mon, 15 May 2017 15:13:16 +0200 Subject: sched/numa: Use down_read_trylock() for the mmap_sem From: Vlastimil Babka <vbabka(a)suse.cz> [ Upstream commit 8655d5497735b288f8a9b458bd22e7d1bf95bb61 ] A customer has reported a soft-lockup when running an intensive memory stress test, where the trace on multiple CPU's looks like this: RIP: 0010:[<ffffffff810c53fe>] [<ffffffff810c53fe>] native_queued_spin_lock_slowpath+0x10e/0x190 ... Call Trace: [<ffffffff81182d07>] queued_spin_lock_slowpath+0x7/0xa [<ffffffff811bc331>] change_protection_range+0x3b1/0x930 [<ffffffff811d4be8>] change_prot_numa+0x18/0x30 [<ffffffff810adefe>] task_numa_work+0x1fe/0x310 [<ffffffff81098322>] task_work_run+0x72/0x90 Further investigation showed that the lock contention here is pmd_lock(). The task_numa_work() function makes sure that only one thread is let to perform the work in a single scan period (via cmpxchg), but if there's a thread with mmap_sem locked for writing for several periods, multiple threads in task_numa_work() can build up a convoy waiting for mmap_sem for read and then all get unblocked at once. This patch changes the down_read() to the trylock version, which prevents the build up. For a workload experiencing mmap_sem contention, it's probably better to postpone the NUMA balancing work anyway. This seems to have fixed the soft lockups involving pmd_lock(), which is in line with the convoy theory. Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Acked-by: Rik van Riel <riel(a)redhat.com> Acked-by: Mel Gorman <mgorman(a)techsingularity.net> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Link: http://lkml.kernel.org/r/20170515131316.21909-1-vbabka@suse.cz Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- kernel/sched/fair.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2429,7 +2429,8 @@ void task_numa_work(struct callback_head return; - down_read(&mm->mmap_sem); + if (!down_read_trylock(&mm->mmap_sem)) + return; vma = find_vma(mm, start); if (!vma) { reset_ptenuma_scan(p); Patches currently in stable-queue which might be from vbabka(a)suse.cz are queue-4.9/sched-numa-use-down_read_trylock-for-the-mmap_sem.patch queue-4.9/mm-vmstat-remove-spurious-warn-during-zoneinfo-print.patch

7 years, 6 months

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Patch "sched/deadline: Use the revised wakeup rule for suspending constrained dl tasks" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled sched/deadline: Use the revised wakeup rule for suspending constrained dl tasks to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: sched-deadline-use-the-revised-wakeup-rule-for-suspending-constrained-dl-tasks.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Daniel Bristot de Oliveira <bristot(a)redhat.com> Date: Mon, 29 May 2017 16:24:03 +0200 Subject: sched/deadline: Use the revised wakeup rule for suspending constrained dl tasks From: Daniel Bristot de Oliveira <bristot(a)redhat.com> [ Upstream commit 3effcb4247e74a51f5d8b775a1ee4abf87cc089a ] We have been facing some problems with self-suspending constrained deadline tasks. The main reason is that the original CBS was not designed for such sort of tasks. One problem reported by Xunlei Pang takes place when a task suspends, and then is awakened before the deadline, but so close to the deadline that its remaining runtime can cause the task to have an absolute density higher than allowed. In such situation, the original CBS assumes that the task is facing an early activation, and so it replenishes the task and set another deadline, one deadline in the future. This rule works fine for implicit deadline tasks. Moreover, it allows the system to adapt the period of a task in which the external event source suffered from a clock drift. However, this opens the window for bandwidth leakage for constrained deadline tasks. For instance, a task with the following parameters: runtime = 5 ms deadline = 7 ms [density] = 5 / 7 = 0.71 period = 1000 ms If the task runs for 1 ms, and then suspends for another 1ms, it will be awakened with the following parameters: remaining runtime = 4 laxity = 5 presenting a absolute density of 4 / 5 = 0.80. In this case, the original CBS would assume the task had an early wakeup. Then, CBS will reset the runtime, and the absolute deadline will be postponed by one relative deadline, allowing the task to run. The problem is that, if the task runs this pattern forever, it will keep receiving bandwidth, being able to run 1ms every 2ms. Following this behavior, the task would be able to run 500 ms in 1 sec. Thus running more than the 5 ms / 1 sec the admission control allowed it to run. Trying to address the self-suspending case, Luca Abeni, Giuseppe Lipari, and Juri Lelli [1] revisited the CBS in order to deal with self-suspending tasks. In the new approach, rather than replenishing/postponing the absolute deadline, the revised wakeup rule adjusts the remaining runtime, reducing it to fit into the allowed density. A revised version of the idea is: At a given time t, the maximum absolute density of a task cannot be higher than its relative density, that is: runtime / (deadline - t) <= dl_runtime / dl_deadline Knowing the laxity of a task (deadline - t), it is possible to move it to the other side of the equality, thus enabling to define max remaining runtime a task can use within the absolute deadline, without over-running the allowed density: runtime = (dl_runtime / dl_deadline) * (deadline - t) For instance, in our previous example, the task could still run: runtime = ( 5 / 7 ) * 5 runtime = 3.57 ms Without causing damage for other deadline tasks. It is note worthy that the laxity cannot be negative because that would cause a negative runtime. Thus, this patch depends on the patch: df8eac8cafce ("sched/deadline: Throttle a constrained deadline task activated after the deadline") Which throttles a constrained deadline task activated after the deadline. Finally, it is also possible to use the revised wakeup rule for all other tasks, but that would require some more discussions about pros and cons. Reported-by: Xunlei Pang <xpang(a)redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot(a)redhat.com> [peterz: replaced dl_is_constrained with dl_is_implicit] Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Cc: Juri Lelli <juri.lelli(a)arm.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Luca Abeni <luca.abeni(a)santannapisa.it> Cc: Mike Galbraith <efault(a)gmx.de> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Romulo Silva de Oliveira <romulo.deoliveira(a)ufsc.br> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Tommaso Cucinotta <tommaso.cucinotta(a)sssup.it> Link: http://lkml.kernel.org/r/5c800ab3a74a168a84ee5f3f84d12a02e11383be.149580380… Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- include/linux/sched.h | 1 kernel/sched/core.c | 2 kernel/sched/deadline.c | 98 ++++++++++++++++++++++++++++++++++++++++++------ 3 files changed, 89 insertions(+), 12 deletions(-) --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1412,6 +1412,7 @@ struct sched_dl_entity { u64 dl_deadline; /* relative deadline of each instance */ u64 dl_period; /* separation of two instances (period) */ u64 dl_bw; /* dl_runtime / dl_deadline */ + u64 dl_density; /* dl_runtime / dl_deadline */ /* * Actual scheduling parameters. Initialized with the values above, --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2184,6 +2184,7 @@ void __dl_clear_params(struct task_struc dl_se->dl_period = 0; dl_se->flags = 0; dl_se->dl_bw = 0; + dl_se->dl_density = 0; dl_se->dl_throttled = 0; dl_se->dl_yielded = 0; @@ -3912,6 +3913,7 @@ __setparam_dl(struct task_struct *p, con dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; dl_se->flags = attr->sched_flags; dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); + dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime); /* * Changing the parameters of a task is 'tricky' and we're not doing --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -484,13 +484,84 @@ static bool dl_entity_overflow(struct sc } /* - * When a -deadline entity is queued back on the runqueue, its runtime and - * deadline might need updating. + * Revised wakeup rule [1]: For self-suspending tasks, rather then + * re-initializing task's runtime and deadline, the revised wakeup + * rule adjusts the task's runtime to avoid the task to overrun its + * density. * - * The policy here is that we update the deadline of the entity only if: - * - the current deadline is in the past, - * - using the remaining runtime with the current deadline would make - * the entity exceed its bandwidth. + * Reasoning: a task may overrun the density if: + * runtime / (deadline - t) > dl_runtime / dl_deadline + * + * Therefore, runtime can be adjusted to: + * runtime = (dl_runtime / dl_deadline) * (deadline - t) + * + * In such way that runtime will be equal to the maximum density + * the task can use without breaking any rule. + * + * [1] Luca Abeni, Giuseppe Lipari, and Juri Lelli. 2015. Constant + * bandwidth server revisited. SIGBED Rev. 11, 4 (January 2015), 19-24. + */ +static void +update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq) +{ + u64 laxity = dl_se->deadline - rq_clock(rq); + + /* + * If the task has deadline < period, and the deadline is in the past, + * it should already be throttled before this check. + * + * See update_dl_entity() comments for further details. + */ + WARN_ON(dl_time_before(dl_se->deadline, rq_clock(rq))); + + dl_se->runtime = (dl_se->dl_density * laxity) >> 20; +} + +/* + * Regarding the deadline, a task with implicit deadline has a relative + * deadline == relative period. A task with constrained deadline has a + * relative deadline <= relative period. + * + * We support constrained deadline tasks. However, there are some restrictions + * applied only for tasks which do not have an implicit deadline. See + * update_dl_entity() to know more about such restrictions. + * + * The dl_is_implicit() returns true if the task has an implicit deadline. + */ +static inline bool dl_is_implicit(struct sched_dl_entity *dl_se) +{ + return dl_se->dl_deadline == dl_se->dl_period; +} + +/* + * When a deadline entity is placed in the runqueue, its runtime and deadline + * might need to be updated. This is done by a CBS wake up rule. There are two + * different rules: 1) the original CBS; and 2) the Revisited CBS. + * + * When the task is starting a new period, the Original CBS is used. In this + * case, the runtime is replenished and a new absolute deadline is set. + * + * When a task is queued before the begin of the next period, using the + * remaining runtime and deadline could make the entity to overflow, see + * dl_entity_overflow() to find more about runtime overflow. When such case + * is detected, the runtime and deadline need to be updated. + * + * If the task has an implicit deadline, i.e., deadline == period, the Original + * CBS is applied. the runtime is replenished and a new absolute deadline is + * set, as in the previous cases. + * + * However, the Original CBS does not work properly for tasks with + * deadline < period, which are said to have a constrained deadline. By + * applying the Original CBS, a constrained deadline task would be able to run + * runtime/deadline in a period. With deadline < period, the task would + * overrun the runtime/period allowed bandwidth, breaking the admission test. + * + * In order to prevent this misbehave, the Revisited CBS is used for + * constrained deadline tasks when a runtime overflow is detected. In the + * Revisited CBS, rather than replenishing & setting a new absolute deadline, + * the remaining runtime of the task is reduced to avoid runtime overflow. + * Please refer to the comments update_dl_revised_wakeup() function to find + * more about the Revised CBS rule. */ static void update_dl_entity(struct sched_dl_entity *dl_se, struct sched_dl_entity *pi_se) @@ -500,6 +571,14 @@ static void update_dl_entity(struct sche if (dl_time_before(dl_se->deadline, rq_clock(rq)) || dl_entity_overflow(dl_se, pi_se, rq_clock(rq))) { + + if (unlikely(!dl_is_implicit(dl_se) && + !dl_time_before(dl_se->deadline, rq_clock(rq)) && + !dl_se->dl_boosted)){ + update_dl_revised_wakeup(dl_se, rq); + return; + } + dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline; dl_se->runtime = pi_se->dl_runtime; } @@ -961,11 +1040,6 @@ static void dequeue_dl_entity(struct sch __dequeue_dl_entity(dl_se); } -static inline bool dl_is_constrained(struct sched_dl_entity *dl_se) -{ - return dl_se->dl_deadline < dl_se->dl_period; -} - static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) { struct task_struct *pi_task = rt_mutex_get_top_task(p); @@ -997,7 +1071,7 @@ static void enqueue_task_dl(struct rq *r * If that is the case, the task will be throttled and * the replenishment timer will be set to the next period. */ - if (!p->dl.dl_throttled && dl_is_constrained(&p->dl)) + if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl)) dl_check_constrained_dl(&p->dl); /* Patches currently in stable-queue which might be from bristot(a)redhat.com are queue-4.9/sched-deadline-use-the-revised-wakeup-rule-for-suspending-constrained-dl-tasks.patch

7 years, 6 months

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Patch "s390: move _text symbol to address higher than zero" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled s390: move _text symbol to address higher than zero to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: s390-move-_text-symbol-to-address-higher-than-zero.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Heiko Carstens <heiko.carstens(a)de.ibm.com> Date: Thu, 4 May 2017 09:42:22 +0200 Subject: s390: move _text symbol to address higher than zero From: Heiko Carstens <heiko.carstens(a)de.ibm.com> [ Upstream commit d04a4c76f71dd5335f8e499b59617382d84e2b8d ] The perf tool assumes that kernel symbols are never present at address zero. In fact it assumes if functions that map symbols to addresses return zero, that the symbol was not found. Given that s390's _text symbol historically is located at address zero this yields at least a couple of false errors and warnings in one of perf's test cases about not present symbols ("perf test 1"). To fix this simply move the _text symbol to address 0x200, just behind the initial psw and channel program located at the beginning of the kernel image. This is now hard coded within the linker script. I tried a nicer solution which moves the initial psw and channel program into an own section. However that would move the symbols within the "real" head.text section to different addresses, since the ".org" statements within head.S are relative to the head.text section. If there is a new section in front, everything else will be moved. Alternatively I could have adjusted all ".org" statements. But this current solution seems to be the easiest one, since nobody really cares where the _text symbol is actually located. Reported-by: Zvonko Kosic <zkosic(a)linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens(a)de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky(a)de.ibm.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/s390/kernel/vmlinux.lds.S | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -31,8 +31,14 @@ SECTIONS { . = 0x00000000; .text : { - _text = .; /* Text and read-only data */ + /* Text and read-only data */ HEAD_TEXT + /* + * E.g. perf doesn't like symbols starting at address zero, + * therefore skip the initial PSW and channel program located + * at address zero and let _text start at 0x200. + */ + _text = 0x200; TEXT_TEXT SCHED_TEXT CPUIDLE_TEXT Patches currently in stable-queue which might be from heiko.carstens(a)de.ibm.com are queue-4.9/s390-move-_text-symbol-to-address-higher-than-zero.patch

7 years, 6 months

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Patch "rtc: snvs: fix an incorrect check of return value" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled rtc: snvs: fix an incorrect check of return value to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: rtc-snvs-fix-an-incorrect-check-of-return-value.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Pan Bian <bianpan2016(a)163.com> Date: Sun, 23 Apr 2017 13:43:24 +0800 Subject: rtc: snvs: fix an incorrect check of return value From: Pan Bian <bianpan2016(a)163.com> [ Upstream commit 758929005f06f954b7e1c87a1c9fdb44157b228f ] Function devm_regmap_init_mmio() returns an ERR_PTR on error. However, in function snvs_rtc_probe() its return value is checked against NULL. This patch fixes it by checking the return value with IS_ERR(). Signed-off-by: Pan Bian <bianpan2016(a)163.com> Signed-off-by: Alexandre Belloni <alexandre.belloni(a)free-electrons.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/rtc/rtc-snvs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/rtc/rtc-snvs.c +++ b/drivers/rtc/rtc-snvs.c @@ -257,7 +257,7 @@ static int snvs_rtc_probe(struct platfor of_property_read_u32(pdev->dev.of_node, "offset", &data->offset); } - if (!data->regmap) { + if (IS_ERR(data->regmap)) { dev_err(&pdev->dev, "Can't find snvs syscon\n"); return -ENODEV; } Patches currently in stable-queue which might be from bianpan2016(a)163.com are queue-4.9/cx25840-fix-unchecked-return-values.patch queue-4.9/usb-dwc3-keystone-check-return-value.patch queue-4.9/rtc-snvs-fix-an-incorrect-check-of-return-value.patch

7 years, 6 months

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Patch "s390/dasd: fix hanging safe offline" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled s390/dasd: fix hanging safe offline to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: s390-dasd-fix-hanging-safe-offline.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From foo@baz Mon Apr 9 17:09:24 CEST 2018 From: Stefan Haberland <sth(a)linux.vnet.ibm.com> Date: Thu, 18 May 2017 13:24:45 +0200 Subject: s390/dasd: fix hanging safe offline From: Stefan Haberland <sth(a)linux.vnet.ibm.com> [ Upstream commit e8ac01555d9e464249e8bb122337d6d6e5589ccc ] The safe offline processing may hang forever because it waits for I/O which can not be started because of the offline flag that prevents new I/O from being started. Allow I/O to be started during safe offline processing because in this special case we take care that the queues are empty before throwing away the device. Signed-off-by: Stefan Haberland <sth(a)linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky(a)de.ibm.com> Signed-off-by: Sasha Levin <alexander.levin(a)microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- drivers/s390/block/dasd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -1950,8 +1950,12 @@ static int __dasd_device_is_unusable(str { int mask = ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM); - if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) { - /* dasd is being set offline. */ + if (test_bit(DASD_FLAG_OFFLINE, &device->flags) && + !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) { + /* + * dasd is being set offline + * but it is no safe offline where we have to allow I/O + */ return 1; } if (device->stopped) { Patches currently in stable-queue which might be from sth(a)linux.vnet.ibm.com are queue-4.9/s390-dasd-fix-hanging-safe-offline.patch

7 years, 6 months

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