On 8/15/21 2:27 PM, Sven Eckelmann wrote: >> mm, slub: convert kmem_cpu_slab protection to local_lock >> >> Embed local_lock into struct kmem_cpu_slab and use the irq-safe versions >> of local_lock instead of plain local_irq_save/restore. On !PREEMPT_RT >> that's equivalent, with better lockdep visibility. On PREEMPT_RT that >> means better preemption. > [...] > > Looks like this change breaks booting when 64BIT+LOCK_STAT is enabled on > x86_64: OK reproduced. Thanks, will investigate. > general protection fault, maybe for address 0xffff888007fcf1c8: 0000 [#1] NOPTI > CPU: 0 PID: 0 Comm: swapper Not tainted 5.14.0-rc5+ #7 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 > RIP: 0010:kmem_cache_alloc+0x81/0x180 > Code: 79 48 00 4c 8b 41 38 0f 84 89 00 00 00 4d 85 c0 0f 84 80 00 00 00 41 8b 44 24 28 49 8b 3c 24 48 8d 4a 01 49 8b 1c 00 4c 89 c0 <48> 0f c7 4f 38 0f 943 > RSP: 0000:ffffffff81803c10 EFLAGS: 00000286 > RAX: ffff88800244e7c0 RBX: ffff88800244e800 RCX: 0000000000000024 > RDX: 0000000000000023 RSI: 0000000000000100 RDI: ffff888007fcf190 > RBP: ffffffff81803c38 R08: ffff88800244e7c0 R09: 0000000000000dc0 > R10: 0000000000004000 R11: 0000000000000000 R12: ffff8880024413c0 > R13: ffffffff810d18f4 R14: 0000000000000dc0 R15: 0000000000000100 > FS: 0000000000000000(0000) GS:ffffffff81840000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff888002001000 CR3: 0000000001824000 CR4: 00000000000006b0 > Call Trace: > __get_vm_area_node.constprop.0.isra.0+0x74/0x150 > __vmalloc_node_range+0x5a/0x2b0 > ? kernel_clone+0x88/0x390 > ? copy_process+0x1ac/0x17e0 > copy_process+0x768/0x17e0 > ? kernel_clone+0x88/0x390 > kernel_clone+0x88/0x390 > ? _vm_unmap_aliases.part.0+0xe9/0x110 > ? change_page_attr_set_clr+0x10d/0x180 > kernel_thread+0x43/0x50 > ? rest_init+0x100/0x100 > rest_init+0x1e/0x100 > arch_call_rest_init+0x9/0xc > start_kernel+0x481/0x493 > x86_64_start_reservations+0x24/0x26 > x86_64_start_kernel+0x80/0x84 > secondary_startup_64_no_verify+0xc2/0xcb > random: get_random_bytes called from oops_exit+0x34/0x60 with crng_init=0 > ---[ end trace 2cac18ac38f640c1 ]--- > RIP: 0010:kmem_cache_alloc+0x81/0x180 > Code: 79 48 00 4c 8b 41 38 0f 84 89 00 00 00 4d 85 c0 0f 84 80 00 00 00 41 8b 44 24 28 49 8b 3c 24 48 8d 4a 01 49 8b 1c 00 4c 89 c0 <48> 0f c7 4f 38 0f 943 > RSP: 0000:ffffffff81803c10 EFLAGS: 00000286 > RAX: ffff88800244e7c0 RBX: ffff88800244e800 RCX: 0000000000000024 > RDX: 0000000000000023 RSI: 0000000000000100 RDI: ffff888007fcf190 > RBP: ffffffff81803c38 R08: ffff88800244e7c0 R09: 0000000000000dc0 > R10: 0000000000004000 R11: 0000000000000000 R12: ffff8880024413c0 > R13: ffffffff810d18f4 R14: 0000000000000dc0 R15: 0000000000000100 > FS: 0000000000000000(0000) GS:ffffffff81840000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff888002001000 CR3: 0000000001824000 CR4: 00000000000006b0 > Kernel panic - not syncing: Attempted to kill the idle task! > ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- > > > This was tested in qemu-system-x86_64 (from Debian Bullseye) with > > cat > .config << "EOF" > # CONFIG_LOCALVERSION_AUTO is not set > # CONFIG_SWAP is not set > # CONFIG_CROSS_MEMORY_ATTACH is not set > # CONFIG_UTS_NS is not set > # CONFIG_TIME_NS is not set > # CONFIG_PID_NS is not set > # CONFIG_COMPAT_BRK is not set > # CONFIG_SLAB_MERGE_DEFAULT is not set > # CONFIG_RETPOLINE is not set > # CONFIG_X86_EXTENDED_PLATFORM is not set > # CONFIG_SCHED_OMIT_FRAME_POINTER is not set > # CONFIG_X86_MCE is not set > # CONFIG_X86_IOPL_IOPERM is not set > # CONFIG_MICROCODE is not set > # CONFIG_MTRR_SANITIZER is not set > # CONFIG_RELOCATABLE is not set > # CONFIG_SUSPEND is not set > # CONFIG_ACPI is not set > # CONFIG_DMIID is not set > # CONFIG_VIRTUALIZATION is not set > # CONFIG_SECCOMP is not set > # CONFIG_STACKPROTECTOR is not set > # CONFIG_BLK_DEV_BSG is not set > # CONFIG_MQ_IOSCHED_DEADLINE is not set > # CONFIG_MQ_IOSCHED_KYBER is not set > # CONFIG_BINFMT_ELF is not set > # CONFIG_BINFMT_SCRIPT is not set > # CONFIG_COMPACTION is not set > # CONFIG_STANDALONE is not set > # CONFIG_PREVENT_FIRMWARE_BUILD is not set > # CONFIG_BLK_DEV is not set > # CONFIG_INPUT_KEYBOARD is not set > # CONFIG_INPUT_MOUSE is not set > # CONFIG_SERIO is not set > # CONFIG_LEGACY_PTYS is not set > # CONFIG_LDISC_AUTOLOAD is not set > CONFIG_SERIAL_8250=y > CONFIG_SERIAL_8250_CONSOLE=y > # CONFIG_HW_RANDOM is not set > # CONFIG_DEVMEM is not set > # CONFIG_HWMON is not set > # CONFIG_HID is not set > # CONFIG_USB_SUPPORT is not set > # CONFIG_VIRTIO_MENU is not set > # CONFIG_VHOST_MENU is not set > # CONFIG_X86_PLATFORM_DEVICES is not set > # CONFIG_IOMMU_SUPPORT is not set > # CONFIG_MANDATORY_FILE_LOCKING is not set > # CONFIG_DNOTIFY is not set > # CONFIG_INOTIFY_USER is not set > # CONFIG_MISC_FILESYSTEMS is not set > # CONFIG_SYMBOLIC_ERRNAME is not set > CONFIG_FRAME_WARN=1024 > # CONFIG_SECTION_MISMATCH_WARN_ONLY is not set > CONFIG_DEBUG_KERNEL=y > CONFIG_LOCK_STAT=y > # CONFIG_FTRACE is not set > # CONFIG_X86_VERBOSE_BOOTUP is not set > CONFIG_UNWINDER_FRAME_POINTER=y > # CONFIG_RUNTIME_TESTING_MENU is not set > CONFIG_64BIT=y > EOF > > make ARCH=x86_64 olddefconfig > make ARCH=x86_64 all > > qemu-system-x86_64 -nographic -kernel arch/x86/boot/bzImage -append console=ttyS0 > > Here is the bisect log: > > # bad: [4b358aabb93a2c654cd1dcab1a25a589f6e2b153] Add linux-next specific files for 20210813 > # good: [36a21d51725af2ce0700c6ebcb6b9594aac658a6] Linux 5.14-rc5 > git bisect start 'HEAD' 'v5.14-rc5' > # good: [204808b2ca750e27cbad3455f7cb4368c4f5b260] Merge remote-tracking branch 'crypto/master' > git bisect good 204808b2ca750e27cbad3455f7cb4368c4f5b260 > # good: [2201162fca73b487152bcff2ebb0f85c1dde8479] Merge remote-tracking branch 'tip/auto-latest' > git bisect good 2201162fca73b487152bcff2ebb0f85c1dde8479 > # good: [41f97b6df1c8fd9fa828967a687693454c4ce888] Merge remote-tracking branch 'staging/staging-next' > git bisect good 41f97b6df1c8fd9fa828967a687693454c4ce888 > # good: [797896d32d52af43fc9b0099a198ef29c2ca0138] Merge remote-tracking branch 'userns/for-next' > git bisect good 797896d32d52af43fc9b0099a198ef29c2ca0138 > # bad: [5c7e12cc3d39b5cfc0d1a470139e4e89f3b147ed] arch: Kconfig: fix spelling mistake "seperate" -> "separate" > git bisect bad 5c7e12cc3d39b5cfc0d1a470139e4e89f3b147ed > # bad: [3535cf93a31ecd8595744881dbbda666cf61be48] add-mmap_assert_locked-annotations-to-find_vma-fix > git bisect bad 3535cf93a31ecd8595744881dbbda666cf61be48 > # bad: [ac90b3dacf327cecda9f3dabc0051c7332770224] mm/debug_vm_pgtable: use struct pgtable_debug_args in PGD and P4D modifying tests > git bisect bad ac90b3dacf327cecda9f3dabc0051c7332770224 > # good: [3a7ac8f97abde2d6ec973a00a449c45b9642a15a] mm, slub: do initial checks in ___slab_alloc() with irqs enabled > git bisect good 3a7ac8f97abde2d6ec973a00a449c45b9642a15a > # good: [1c84f3c916405dc3d62cfca55fb2a84de9d7f31e] mm, slub: fix memory and cpu hotplug related lock ordering issues > git bisect good 1c84f3c916405dc3d62cfca55fb2a84de9d7f31e > # bad: [6ac9c394652dbba1181268cb09513edbd733685c] mm/debug_vm_pgtable: introduce struct pgtable_debug_args > git bisect bad 6ac9c394652dbba1181268cb09513edbd733685c > # good: [35a6f4bcf4ad9c8c0208ea48044539a952859b3a] mm, slub: make slab_lock() disable irqs with PREEMPT_RT > git bisect good 35a6f4bcf4ad9c8c0208ea48044539a952859b3a > # good: [03e736e3ca2c0a48822609a89ffa0329f4eb5aae] mm, slub: use migrate_disable() on PREEMPT_RT > git bisect good 03e736e3ca2c0a48822609a89ffa0329f4eb5aae > # bad: [3f57fd12e8b7eb77412623c347566fb83ec5e764] mm, slub: convert kmem_cpu_slab protection to local_lock > git bisect bad 3f57fd12e8b7eb77412623c347566fb83ec5e764 > # first bad commit: [3f57fd12e8b7eb77412623c347566fb83ec5e764] mm, slub: convert kmem_cpu_slab protection to local_lock > > I haven't checked what part of the change is actually causing the problem > > Kind regards, > Sven >
