Documentation: move teaching/labs/conf.py to teaching/ #8

tavip · 2018-02-23T23:18:13Z

Fixes #7

The conf.py needs to be at the top of the namespace directory so move it where it belongs. And since we now have multiple subdirectories and includes are relative to current file directory, the common substitution will not longer work for all files. To fix this, just move the contents of subst.hrst directly to rst_epilog in conf.py. Fixes the following errors: deferred_work.rst:721: ERROR: Undefined substitution referenced: "LXR". deferred_work.rst:721: ERROR: Unknown target name: "lxr". interrupts.rst:688: ERROR: Undefined substitution referenced: "LXR". interrupts.rst:688: ERROR: Unknown target name: "lxr". kernel_api.rst:739: ERROR: Unexpected indentation. kernel_api.rst:582: ERROR: Undefined substitution referenced: "LXR". kernel_api.rst:582: ERROR: Unknown target name: "lxr". kernel_modules.rst:810: ERROR: Undefined substitution referenced: "LXR". kernel_modules.rst:939: ERROR: Undefined substitution referenced: "LXR". kernel_modules.rst:810: ERROR: Unknown target name: "lxr". kernel_modules.rst:939: ERROR: Unknown target name: "lxr". Signed-off-by: Octavian Purdila <tavi@cs.pub.ro>

We would not be transmitting using the correct SYSTEMPORT transmit queue during ndo_select_queue() which looks up the internal TX ring map because while establishing the mapping we would be off by 4, so for instance, when we populate switch port mappings we would be doing: switch port 0, queue 0 -> ring index #0 switch port 0, queue 1 -> ring index #1 ... switch port 0, queue 3 -> ring index #3 switch port 1, queue 0 -> ring index linux-kernel-labs#8 (4 + 4 * 1) ... instead of using ring index #4. This would cause our ndo_select_queue() to use the fallback queue mechanism which would pick up an incorrect ring for that switch port. Fix this by using the correct switch queue number instead of SYSTEMPORT queue number. Fixes: 25c4407 ("net: systemport: Simplify queue mapping logic") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>

This BUG halt was reported a while back, but the patch somehow got missed: PID: 2879 TASK: c16adaa0 CPU: 1 COMMAND: "sctpn" #0 [f418dd28] crash_kexec at c04a7d8c #1 [f418dd7c] oops_end at c0863e02 #2 [f418dd90] do_invalid_op at c040aaca #3 [f418de28] error_code (via invalid_op) at c08631a5 EAX: f34baac0 EBX: 00000090 ECX: f418deb0 EDX: f5542950 EBP: 00000000 DS: 007b ESI: f34ba800 ES: 007b EDI: f418dea0 GS: 00e0 CS: 0060 EIP: c046fa5e ERR: ffffffff EFLAGS: 00010286 #4 [f418de5c] add_timer at c046fa5e #5 [f418de68] sctp_do_sm at f8db8c77 [sctp] #6 [f418df30] sctp_primitive_SHUTDOWN at f8dcc1b5 [sctp] linux-kernel-labs#7 [f418df48] inet_shutdown at c080baf9 linux-kernel-labs#8 [f418df5c] sys_shutdown at c079eedf linux-kernel-labs#9 [f418df7] sys_socketcall at c079fe88 EAX: ffffffda EBX: 0000000d ECX: bfceea90 EDX: 0937af98 DS: 007b ESI: 0000000c ES: 007b EDI: b7150ae4 SS: 007b ESP: bfceea7c EBP: bfceeaa8 GS: 0033 CS: 0073 EIP: b775c424 ERR: 00000066 EFLAGS: 00000282 It appears that the side effect that starts the shutdown timer was processed multiple times, which can happen as multiple paths can trigger it. This of course leads to the BUG halt in add_timer getting called. Fix seems pretty straightforward, just check before the timer is added if its already been started. If it has mod the timer instead to min(current expiration, new expiration) Its been tested but not confirmed to fix the problem, as the issue has only occured in production environments where test kernels are enjoined from being installed. It appears to be a sane fix to me though. Also, recentely, Jere found a reproducer posted on list to confirm that this resolves the issues Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yasevich <vyasevich@gmail.com> CC: "David S. Miller" <davem@davemloft.net> CC: jere.leppanen@nokia.com CC: marcelo.leitner@gmail.com CC: netdev@vger.kernel.org Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>

I/O requests may be held in scheduler queue because of resource contention. The starvation scenario was handled properly in the regular completion path but we failed to account for it during I/O submission. This lead to the hang captured below. Make sure we run the queue when resource contention is encountered in the submission path. [ 39.054963] scsi 13:0:0:0: rejecting I/O to dead device [ 39.058700] scsi 13:0:0:0: rejecting I/O to dead device [ 39.087855] sd 13:0:0:1: [sdd] Synchronizing SCSI cache [ 39.088909] scsi 13:0:0:1: rejecting I/O to dead device [ 39.095351] scsi 13:0:0:1: rejecting I/O to dead device [ 39.096962] scsi 13:0:0:1: rejecting I/O to dead device [ 247.021859] INFO: task scsi-stress-rem:813 blocked for more than 122 seconds. [ 247.023258] Not tainted 5.8.0-rc2 linux-kernel-labs#8 [ 247.024069] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 247.025331] scsi-stress-rem D 0 813 802 0x00004000 [ 247.025334] Call Trace: [ 247.025354] __schedule+0x504/0x55f [ 247.027987] schedule+0x72/0xa8 [ 247.027991] blk_mq_freeze_queue_wait+0x63/0x8c [ 247.027994] ? do_wait_intr_irq+0x7a/0x7a [ 247.027996] blk_cleanup_queue+0x4b/0xc9 [ 247.028000] __scsi_remove_device+0xf6/0x14e [ 247.028002] scsi_remove_device+0x21/0x2b [ 247.029037] sdev_store_delete+0x58/0x7c [ 247.029041] kernfs_fop_write+0x10d/0x14f [ 247.031281] vfs_write+0xa2/0xdf [ 247.032670] ksys_write+0x6b/0xb3 [ 247.032673] do_syscall_64+0x56/0x82 [ 247.034053] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 247.034059] RIP: 0033:0x7f69f39e9008 [ 247.036330] Code: Bad RIP value. [ 247.036331] RSP: 002b:00007ffdd8116498 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 247.037613] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f69f39e9008 [ 247.039714] RDX: 0000000000000002 RSI: 000055cde92a0ab0 RDI: 0000000000000001 [ 247.039715] RBP: 000055cde92a0ab0 R08: 000000000000000a R09: 00007f69f3a79e80 [ 247.039716] R10: 000000000000000a R11: 0000000000000246 R12: 00007f69f3abb780 [ 247.039717] R13: 0000000000000002 R14: 00007f69f3ab6740 R15: 0000000000000002 Link: https://lore.kernel.org/r/20200720025435.812030-1-ming.lei@redhat.com Cc: linux-block@vger.kernel.org Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

The crash was caused by locking an uninitialized lock during init of drm_gem_object. The lock changed in the breaking commit, but the init was not moved accordingly. 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = (ptrval) [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM Modules linked in: msm(+) qcom_spmi_vadc qcom_vadc_common dm_mod usb_f_rndis rmi_i2c rmi_core qnoc_msm8974 icc_smd_rpm pm8941_pwrkey CPU: 2 PID: 1020 Comm: udevd Not tainted 5.10.0-postmarketos-qcom-msm8974 linux-kernel-labs#8 Hardware name: Generic DT based system PC is at ww_mutex_lock+0x20/0xb0 LR is at _msm_gem_new+0x13c/0x298 [msm] pc : [<c0be31e8>] lr : [<bf0b3404>] psr: 20000013 sp : c36e7ad0 ip : c3b3d800 fp : 00000000 r10: 00000001 r9 : c3b22800 r8 : 00000000 r7 : c3b23000 r6 : c3b3d60 r5 : c3b3d60 r4 : 00000000 r3 : c34b4780 r2 : c3b3d6f4 r1 : 00000000 r0 : 00000000 Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5787d Table: 03ae406a DAC: 00000051 Process udevd (pid: 1020, stack limit = 0x(ptrval)) Stack: (0xc36e7ad0 to 0xc36e8000) [...] [<c0be31e8>] (ww_mutex_lock) from [<bf0b3404>] (_msm_gem_new+0x13c/0x298 [msm]) [<bf0b3404>] (_msm_gem_new [msm]) from [<bf0b3aa8>] (_msm_gem_kernel_new+0x20/0x190 [msm]) [<bf0b3aa8>] (_msm_gem_kernel_new [msm]) from [<bf0b4a30>] (msm_gem_kernel_new+0x24/0x2c [msm]) [<bf0b4a30>] (msm_gem_kernel_new [msm]) from [<bf0b8e2c>] (msm_gpu_init+0x308/0x548 [msm]) [<bf0b8e2c>] (msm_gpu_init [msm]) from [<bf060a90>] (adreno_gpu_init+0x13c/0x240 [msm]) [<bf060a90>] (adreno_gpu_init [msm]) from [<bf062b1c>] (a3xx_gpu_init+0x78/0x1dc [msm]) [<bf062b1c>] (a3xx_gpu_init [msm]) from [<bf05f394>] (adreno_bind+0x1cc/0x274 [msm]) [<bf05f394>] (adreno_bind [msm]) from [<c087a254>] (component_bind_all+0x11c/0x278) [<c087a254>] (component_bind_all) from [<bf0b11d4>] (msm_drm_bind+0x18c/0x5b4 [msm]) [<bf0b11d4>] (msm_drm_bind [msm]) from [<c0879ea0>] (try_to_bring_up_master+0x200/0x2c8) [<c0879ea0>] (try_to_bring_up_master) from [<c087a648>] (component_master_add_with_match+0xc8/0xfc) [<c087a648>] (component_master_add_with_match) from [<bf0b0c3c>] (msm_pdev_probe+0x288/0x2c4 [msm]) [<bf0b0c3c>] (msm_pdev_probe [msm]) from [<c08844cc>] (platform_drv_probe+0x48/0x98) [<c08844cc>] (platform_drv_probe) from [<c0881cc4>] (really_probe+0x108/0x528) [<c0881cc4>] (really_probe) from [<c0882480>] (driver_probe_device+0x78/0x1d4) [<c0882480>] (driver_probe_device) from [<c08828dc>] (device_driver_attach+0xa8/0xb0) [<c08828dc>] (device_driver_attach) from [<c0882998>] (__driver_attach+0xb4/0x154) [<c0882998>] (__driver_attach) from [<c087fa1c>] (bus_for_each_dev+0x78/0xb8) [<c087fa1c>] (bus_for_each_dev) from [<c0880e98>] (bus_add_driver+0x10c/0x208) [<c0880e98>] (bus_add_driver) from [<c0883504>] (driver_register+0x88/0x118) [<c0883504>] (driver_register) from [<c0302098>] (do_one_initcall+0x50/0x2b0) [<c0302098>] (do_one_initcall) from [<c03bace4>] (do_init_module+0x60/0x288) [<c03bace4>] (do_init_module) from [<c03bdf1c>] (sys_finit_module+0xd4/0x120) [<c03bdf1c>] (sys_finit_module) from [<c0300060>] (ret_fast_syscall+0x0/0x54) Exception stack(0xc36e7fa8 to 0xc36e7ff0) 7fa0: 00020000 00000000 00000007 b6edd5b0 00000000 b6f2ff20 7fc0: 00020000 00000000 0000017b 0000017b b6eef980 bedc3a54 00473c99 00000000 7fe0: b6edd5b0 bedc3918 b6ed8a5f b6f6a8b0 Code: e3c3303f e593300c e1a04000 f590f000 (e1940f9f) ---[ end trace 277e2a3da40bbb76 ]--- Fixes: 6c0e3ea ("drm/msm/gem: Switch over to obj->resv for locking") Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com> Signed-off-by: Rob Clark <robdclark@chromium.org>

We had kernel panic, it is caused by unload module and last close confirmation. call trace: [1196029.743127] free_sess+0x15/0x50 [rtrs_client] [1196029.743128] rtrs_clt_close+0x4c/0x70 [rtrs_client] [1196029.743129] ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client] [1196029.743130] close_rtrs+0x25/0x50 [rnbd_client] [1196029.743131] rnbd_client_exit+0x93/0xb99 [rnbd_client] [1196029.743132] __x64_sys_delete_module+0x190/0x260 And in the crashdump confirmation kworker is also running. PID: 6943 TASK: ffff9e2ac8098000 CPU: 4 COMMAND: "kworker/4:2" #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client] #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client] linux-kernel-labs#7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client] linux-kernel-labs#8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client] linux-kernel-labs#9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client] The problem is both code path try to close same session, which lead to panic. To fix it, just skip the sess if the refcount already drop to 0. Fixes: f7a7a5c ("block/rnbd: client: main functionality") Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>

When a virtio pci device undergo surprise removal (aka async removal in PCIe spec), mark the device as broken so that any upper layer drivers can abort any outstanding operation. When a virtio net pci device undergo surprise removal which is used by a NetworkManager, a below call trace was observed. kernel:watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [kworker/1:1:27059] watchdog: BUG: soft lockup - CPU#1 stuck for 52s! [kworker/1:1:27059] CPU: 1 PID: 27059 Comm: kworker/1:1 Tainted: G S W I L 5.13.0-hotplug+ linux-kernel-labs#8 Hardware name: Dell Inc. PowerEdge R640/0H28RR, BIOS 2.9.4 11/06/2020 Workqueue: events linkwatch_event RIP: 0010:virtnet_send_command+0xfc/0x150 [virtio_net] Call Trace: virtnet_set_rx_mode+0xcf/0x2a7 [virtio_net] ? __hw_addr_create_ex+0x85/0xc0 __dev_mc_add+0x72/0x80 igmp6_group_added+0xa7/0xd0 ipv6_mc_up+0x3c/0x60 ipv6_find_idev+0x36/0x80 addrconf_add_dev+0x1e/0xa0 addrconf_dev_config+0x71/0x130 addrconf_notify+0x1f5/0xb40 ? rtnl_is_locked+0x11/0x20 ? __switch_to_asm+0x42/0x70 ? finish_task_switch+0xaf/0x2c0 ? raw_notifier_call_chain+0x3e/0x50 raw_notifier_call_chain+0x3e/0x50 netdev_state_change+0x67/0x90 linkwatch_do_dev+0x3c/0x50 __linkwatch_run_queue+0xd2/0x220 linkwatch_event+0x21/0x30 process_one_work+0x1c8/0x370 worker_thread+0x30/0x380 ? process_one_work+0x370/0x370 kthread+0x118/0x140 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x1f/0x30 Hence, add the ability to abort the command on surprise removal which prevents infinite loop and system lockup. Signed-off-by: Parav Pandit <parav@nvidia.com> Link: https://lore.kernel.org/r/20210721142648.1525924-5-parav@nvidia.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

tavip force-pushed the lktp-3 branch from 02cfd5d to 77def8f Compare February 23, 2018 23:56

tavip pushed a commit to linux-kernel-labs/linux-kernel-labs.github.io that referenced this pull request Feb 23, 2018

Publish lktp-3 (built from linux-kernel-labs/linux#8)

d8311ce

tavip requested review from dbaluta, razvand, andanicolae, alexandrasandulescu and valighita February 23, 2018 23:58

dbaluta approved these changes Feb 24, 2018

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tavip merged commit 24cfdef into linux-kernel-labs:master Feb 24, 2018

tavip deleted the lktp-3 branch February 24, 2018 16:51

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Documentation: move teaching/labs/conf.py to teaching/ #8

Documentation: move teaching/labs/conf.py to teaching/ #8

tavip commented Feb 23, 2018 •

edited

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Documentation: move teaching/labs/conf.py to teaching/ #8

Documentation: move teaching/labs/conf.py to teaching/ #8

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tavip commented Feb 23, 2018 • edited Loading

tavip commented Feb 23, 2018 •

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