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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?zROgUNIkinQdGmpQ4xPZB7YARKrWsmjrheXQmLz0nvuiSk+oeUoyvmLVpR8K?= =?us-ascii?Q?tjJT4df7Zmyp0GnZ50NbNUpKKphjqgdEpg7Mu/mRrbfjjjnyWPGy+Yu7yTt7?= =?us-ascii?Q?by/AR3i/A1uvxT4P895OGj7sOGegoEE/tPVlFfwK6vCAMBHIV39+MLGe6QVt?= =?us-ascii?Q?/dCUcCcBnw4f32T8THn2z68BBf1df7EBFZf2uMhsRarpMW8stDkjzVY+uALm?= =?us-ascii?Q?XsLpgWp0EnXrmvT83YeQ/rt5i9tW6XneiEgxQkAkBFOS+DexzJ4Jm5vjWfYw?= =?us-ascii?Q?pfGM4V6hR/Lvxu5ndr8rzMMez01+rRwao3mo/mLpa1Zkd7Y7+vrrhWD3vQuN?= =?us-ascii?Q?SuBOEuO9h4S2qqdDtju7JSsaHAtdF5jclTCfrntM+wj81wOzNcN2z4zfUpYy?= =?us-ascii?Q?myOfifw7vJ38w0lSgx/F05dcsDXqn/14vb0e4zfChG/3gDTDdhjEI495zC0A?= =?us-ascii?Q?JxKv8HePQaMIZw8QcsJvBPk6v/prp2gBw9fotlTqCzhyMIyQuEG+3vFdnkZe?= =?us-ascii?Q?ASV64Mj8N2k1et80SwiNwq7K+4GCcBfQjcTgEAG6Y5AfXot1JeokwKR60cz6?= =?us-ascii?Q?jvw++IL4UMhg78DP9a9W2Zx6GzxUztTGZEiCeJ9OZwB3uDhzVg3oju0ft6Kg?= =?us-ascii?Q?xx4YASnrrB9ZSHttnABc8VIdRByEC67vAWyTSMdbe7+ZmVk/GGWf2YPpHLYb?= =?us-ascii?Q?L9K0SIsyzk5zSqOzHsKNj554hBQ7YGfWs/v78mdN7Y/KQWWk2/9pi8GXvYP1?= =?us-ascii?Q?dV6zazJknKiHzrNXe8aoccrv+ZZNxkzzcsWoBebExi963L3jCNxRt0n9P5Hz?= =?us-ascii?Q?UTvwaPs7JUYbv/r10GRvsNgUT0oOs598V18N23Xs3kDzGsLXcFKEl5C8Q/6R?= =?us-ascii?Q?KLYjlsTJPAnSse8ldhmJwadpr8Sjpi5RKyQr+rdIJGftrjvMdQe3+TuGMrZV?= =?us-ascii?Q?jy7BkpBV7QHXLf4an3sTKJrTTT+fmUFI2QkUV5bRdm1vi1jt0JWZH6RSqX6j?= =?us-ascii?Q?1J38prIu1uGUpJMEEuD7bicWMq3cMEFYSlkhcxLnoHKWjJx4iiXL8Je/d7fx?= =?us-ascii?Q?OgLF8AXBrTJRTT4gPILJv+2zzRaHWXKektZbEjmnEJ5ttrwqWW3UF0mHCueF?= =?us-ascii?Q?kB10Fs1nPF2iwuoKVmNFt0AiqKtnaWYHDQKR7jaIte+zHzye2Ii36rTBvVGk?= =?us-ascii?Q?oRi9rPheDY8DL78yLbqOnX70ylB+VE0J+AVOn13rOB8bWHjXVqgsWk8v9Dmg?= =?us-ascii?Q?308r+iMM/+3re5ttp0Iyk7czK0DhER/d6cb7zxtkvTH5quehP5XDqz3HIhoQ?= =?us-ascii?Q?LbexfsPOYGhcacaTxJLkDJpc8dVfToSxbOiJ3Jc7WgPzH4DSYodLpw9vWthd?= =?us-ascii?Q?9Hna08MfFoAhuvNkbHhrsrVSgjUvq4mvFfAHsvQmFfJG+B6RvvKvgR5n4+Rl?= =?us-ascii?Q?7e0gHqoRB3zWr/h2zZuHqjFrJ1WjP7aN03ga3oM6qXr2UqowXtJN64XEoOXP?= =?us-ascii?Q?mJcf+pChtn2Xni6jQ0IOLxop7f9ZASNXGgfols5aQnN8w1tMCTPBSSeGezt1?= =?us-ascii?Q?Ie1uwzNsPTsrIX56msTvFXov1e7AwEPFYHH2kYVQKPngxQQtH80XzAei3uqW?= =?us-ascii?Q?3l+Uz2JyriIrslT0Od/o5rbPEJp07B8g5sMpY034n9xqzlVU5GfndAqQhlus?= =?us-ascii?Q?0gubcs0388HGVN/rH/pnrHfo0tx4OcwTYRc9wv3ZF6ELH1f9rQBosf/VCPHs?= =?us-ascii?Q?xbR6mo/HNQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b9181171-a9d4-4b3f-24cd-08dee3e35e64 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB4827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Jul 2026 09:11:21.8665 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: yY4yJoYrDf3tGXoQb3Qph4mEtcQNst+Dxzvnz1q5eyVLbghqROg2MsowekiKQnkFEDUniunjdIbbzM113PN1ag== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB6326 Hi Tejun, On Thu, Jul 16, 2026 at 11:30:54AM -1000, Tejun Heo wrote: > This patchset contains three sub-scheduler fixes and a cgroup lock > ordering deadlock fix. > > 0001-sched_ext-Reject-setting-disallow-from-init_task-out.patch > 0002-sched_ext-Take-cgroup_lock-first-in-scx_cgroup_lock.patch > 0003-sched_ext-Skip-sub-disable-teardown-for-never-linked.patch > 0004-sched_ext-Don-t-enable-non-ext-tasks-in-the-sub-sche.patch > > - 0001 makes ops.init_task() setting p->scx.disallow outside the enable > path fail the scheduler. The sub-scheduler disable path could reach the > load-path-only policy revert and silently rewrite a live task's policy. > > - 0002 fixes a three-way deadlock among scx_cgroup_lock(), cgroup teardown > draining the cpu controller's files, and a concurrent cpu.weight write. > Present in released kernels since v6.18 and marked for stable. > > - 0003 fixes a use-after-free when a sub-scheduler whose enable failed > before linking is torn down concurrently with root disable. > > - 0004 gates task enabling on the ext class in the sub-scheduler task > loops. A non-ext task under an SCX_OPS_SWITCH_PARTIAL root could be > marked ENABLED while staying on its own class, corrupting the task state > machine. I randomly triggered the following with this applied, but it looks unrelated to these changes: [ 140.251732] BUG: unable to handle page fault for address: 0000000000020037 [ 140.251914] #PF: supervisor write access in kernel mode [ 140.252020] #PF: error_code(0x0002) - not-present page [ 140.252163] PGD 0 P4D 0 [ 140.252237] Oops: Oops: 0002 [#1] SMP NOPTI [ 140.252339] CPU: 5 UID: 0 PID: 103 Comm: kworker/u65:1 Not tainted 7.1.0-virtme #1 PREEMPT(full) [ 140.252575] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 140.252704] Workqueue: events_unbound scx_watchdog_workfn [ 140.252766] Sched_ext: qmap (enabled+all), task: runnable_at=-1ms [ 140.252768] RIP: 0010:scx_claim_exit+0xfd/0x190 [ 140.252897] Code: 02 00 74 24 65 8b 05 4a ac ce 02 85 c0 75 19 65 8b 05 27 68 ce 02 a9 ff ff ff 7f 75 0b 65 8b 05 a1 a8 ce 02 85 c0 75 46 31 c0 45 0f b1 a7 28 04 00 00 75 14 41 c6 87 b4 03 00 00 01 49 8d bf [ 140.253102] RSP: 0018:ffffc900003f7d10 EFLAGS: 00010046 [ 140.253160] RAX: 0000000000000000 RBX: ffff888125ed5000 RCX: ffffea0004768bb2 [ 140.253232] RDX: 000000008881093f RSI: ffffffff83685140 RDI: ffff888100c45440 [ 140.253316] RBP: 0000000000000001 R08: ffffffff8411c438 R09: ffff888100c45440 [ 140.253406] R10: 00000000000003e5 R11: ffff888100c44780 R12: 0000000000000044 [ 140.253501] R13: 0000000000000000 R14: 0000000000000016 R15: 000000000001fc0f [ 140.253595] FS: 0000000000000000(0000) GS:ffff8882b379a000(0000) knlGS:0000000000000000 [ 140.253681] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 140.253791] CR2: 0000000000020037 CR3: 000000000364c000 CR4: 0000000000750ef0 [ 140.253865] PKRU: 55555554 [ 140.253903] Call Trace: [ 140.253966] [ 140.253996] scx_vexit+0x3a/0x170 [ 140.254041] __scx_exit+0x51/0x70 [ 140.254087] scx_watchdog_workfn+0x25f/0x360 [ 140.254156] ? process_scheduled_works+0x219/0x510 [ 140.254208] process_scheduled_works+0x265/0x510 [ 140.254272] worker_thread+0x226/0x360 [ 140.254311] ? __pfx_worker_thread+0x10/0x10 [ 140.254386] kthread+0x10c/0x140 [ 140.254425] ? __pfx_kthread+0x10/0x10 [ 140.254465] ret_from_fork+0x189/0x330 [ 140.254521] ? __pfx_kthread+0x10/0x10 [ 140.254562] ret_from_fork_asm+0x1a/0x30 [ 140.254608] [ 140.254633] Modules linked in: [ 140.254689] CR2: 0000000000020037 [ 140.254733] ---[ end trace 0000000000000000 ]--- This might be a pre-existent bug, I'll investigate a bit. Thanks, -Andrea > > This is against sched_ext/for-7.2-fixes (0e2f4ab68a89) and also available > in the following git branch: > > https://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git scx-sub-cgroup-fixes > > diffstat follows. > > include/linux/sched/ext.h | 10 +++++----- > kernel/sched/ext/ext.c | 47 ++++++++++++++++++++++++++++++++++++++--------- > 2 files changed, 43 insertions(+), 14 deletions(-) > > -- > tejun