Public bug reported: [Impact] On system with cores > 200, printk during HMAT parsing can create soft lockup: [ 35.769351] watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [swapper/0:1] [ 35.769354] Modules linked in: [ 35.769358] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 6.8.0-1009-nvidia-64k #9~22.04.1-Ubuntu [ 35.769360] Hardware name: NVIDIA PG548-C00/P4975, BIOS 02.02.02 20240729 [ 35.769362] pstate: 81001009 (Nzcv daif -PAN -UAO -TCO +DIT +SSBS BTYPE=--) [ 35.769364] pc : console_flush_all+0x1f0/0x3f0 [ 35.769375] lr : console_flush_all+0x1e8/0x3f0 [ 35.769376] sp : ffff800081b2f870 [ 35.769377] x29: ffff800081b2f870 x28: ffffc06104152a10 x27: ffffc06103390008 [ 35.769378] x26: 0000000000000001 x25: ffffc06103da8a98 x24: 0000000000000000 [ 35.769380] x23: 0000000000000000 x22: ffff800081b2f990 x21: ffff800081b2f98f [ 35.769381] x20: ffffc06104307160 x19: 0000000000000001 x18: 0000000000000000 [ 35.769382] x17: 0000000000000000 x16: 0000000000000000 x15: 6977646e61422073 [ 35.769384] x14: 0000000000000000 x13: 732f424d20303a5d x12: 39322d39325b7465 [ 35.769385] x11: 677261542d726f74 x10: 616974696e492020 x9 : ffffc06100bf35c8 [ 35.769386] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 [ 35.769387] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 [ 35.769389] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 [ 35.769391] Call trace: [ 35.769393] console_flush_all+0x1f0/0x3f0 [ 35.769395] console_unlock+0x70/0x1f8 [ 35.769396] vprintk_emit+0x2e4/0x4b8 [ 35.769398] vprintk_default+0x40/0x80 [ 35.769399] vprintk+0x98/0x150 [ 35.769400] _printk+0x64/0xc0 [ 35.769405] hmat_parse_locality.constprop.0+0x1f4/0x740 [ 35.769416] hmat_parse_subtable+0x58/0xf0 [ 35.769418] acpi_parse_entries_array+0x1fc/0x360 [ 35.769426] acpi_table_parse_entries_array+0xa4/0x170 [ 35.769431] acpi_table_parse_entries+0x4c/0xa0 [ 35.769433] hmat_init+0x14c/0x440 [ 35.769434] do_one_initcall+0x4c/0x368 [ 35.769439] do_initcalls+0x134/0x2c0 [ 35.769442] kernel_init_freeable+0x128/0x2b0 [ 35.769443] kernel_init+0x38/0x240 [ 35.769451] ret_from_fork+0x10/0x20 [ 35.959318] acpi/hmat: Initiator-Target[29-30]:0 MB/s [ 35.964658] acpi/hmat: Initiator-Target[29-31]:0 MB/s [ 35.969997] acpi/hmat: Initiator-Target[29-32]:0 MB/s [ 35.975335] acpi/hmat: Initiator-Target[29-33]:0 MB/s
[Fix] The information isn't that useful, lower the message level to pr_debug() to avoid the issue. [Test] Boot up the system and check dmesg. With the patch applied, no more HMAT spam can be found in kernel message. [Where problems could occur] There can be some obscure race conditions be exposed by booting the kernel faster. ** Affects: linux (Ubuntu) Importance: Undecided Status: Confirmed ** Changed in: linux (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2090982 Title: Prevent soft lockup on boot up To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2090982/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs