On 2/16/23 1:24 AM, Helge Deller wrote: > On 2/16/23 03:50, Jens Axboe wrote: >> On 2/15/23 7:40 PM, John David Anglin wrote: >>> On 2023-02-15 6:02 p.m., Jens Axboe wrote: >>>> This is not related to Helge's patch, 6.1-stable is just still missing: >>>> >>>> commit fcc926bb857949dbfa51a7d95f3f5ebc657f198c >>>> Author: Jens Axboe<axboe@xxxxxxxxx> >>>> Date: Fri Jan 27 09:28:13 2023 -0700 >>>> >>>> io_uring: add a conditional reschedule to the IOPOLL cancelation loop >>>> >>>> and I'm guessing you're running without preempt. >>> With 6.2.0-rc8+, I had a different crash running poll-race-mshot.t: >>> >>> Backtrace: >>> >>> >>> Kernel Fault: Code=15 (Data TLB miss fault) at addr 0000000000000000 >>> CPU: 0 PID: 18265 Comm: poll-race-mshot Not tainted 6.2.0-rc8+ #1 >>> Hardware name: 9000/800/rp3440 >>> >>> YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI >>> PSW: 00010000001001001001000111110000 Not tainted >>> r00-03 00000000102491f0 ffffffffffffffff 000000004020307c ffffffffffffffff >>> r04-07 ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff >>> r08-11 ffffffffffffffff 000000000407ef28 000000000407f838 8400000000800000 >>> r12-15 0000000000000000 0000000040c424e0 0000000040c424e0 0000000040c424e0 >>> r16-19 000000000407fd68 0000000063f08648 0000000040c424e0 000000000a085000 >>> r20-23 00000000000d6b44 000000002faf0800 00000000000000ff 0000000000000002 >>> r24-27 000000000407fa30 000000000407fd68 0000000000000000 0000000040c1e4e0 >>> r28-31 400000000000de84 0000000000000000 0000000000000000 0000000000000002 >>> sr00-03 0000000004081000 0000000000000000 0000000000000000 0000000004081de0 >>> sr04-07 0000000004081000 0000000000000000 0000000000000000 00000000040815a8 >>> >>> IASQ: 0000000004081000 0000000000000000 IAOQ: 0000000000000000 0000000004081590 >>> IIR: 00000000 ISR: 0000000000000000 IOR: 0000000000000000 >>> CPU: 0 CR30: 000000004daf5700 CR31: ffffffffffffefff >>> ORIG_R28: 0000000000000000 >>> IAOQ[0]: 0x0 >>> IAOQ[1]: linear_quiesce+0x0/0x18 [linear] >>> RP(r2): intr_check_sig+0x0/0x3c >>> Backtrace: >>> >>> Kernel panic - not syncing: Kernel Fault >> >> This means very little to me, is it a NULL pointer deref? And where's >> the backtrace? > > I see iopoll.t triggering the kernel to hang on 32-bit kernel. > System gets unresponsive, bug with sysrq-l I get: > > [ 880.020641] sysrq: Show backtrace of all active CPUs > [ 880.024123] sysrq: CPU0: > [ 880.024123] CPU: 0 PID: 7549 Comm: kworker/u32:7 Not tainted 6.1.12-32bit+ #1595 > [ 880.024123] Hardware name: 9000/785/C3700 > [ 880.024123] Workqueue: events_unbound io_ring_exit_work > [ 880.024123] > [ 880.024123] YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI > [ 880.024123] PSW: 00000000000011001111111100001111 Not tainted > [ 880.024123] r00-03 000cff0f 19610540 104f7b70 19610540 > [ 880.024123] r04-07 1921a278 00000000 192c8400 1921b508 > [ 880.024123] r08-11 00000003 0000002e 195fd050 00000004 > [ 880.024123] r12-15 192c8710 10a77000 00000000 00002000 > [ 880.024123] r16-19 1921a210 1240c000 1240c060 1924aff0 > [ 880.024123] r20-23 00000002 00000000 104b4384 00000020 > [ 880.024123] r24-27 00000003 19610548 1921a210 10aba968 > [ 880.024123] r28-31 1094f5c0 0000000e 196105c0 104f7b70 > [ 880.024123] sr00-03 00000000 00001695 00000000 00001695 > [ 880.024123] sr04-07 00000000 00000000 00000000 00000000 > [ 880.024123] > [ 880.024123] IASQ: 00000000 00000000 IAOQ: 104f7b6c 104b4384 > [ 880.024123] IIR: 081f0242 ISR: 00002000 IOR: 00000000 > [ 880.024123] CPU: 0 CR30: 195fd050 CR31: d237ffff > [ 880.024123] ORIG_R28: 00000000 > [ 880.024123] IAOQ[0]: io_do_iopoll+0xb4/0x3a4 > [ 880.024123] IAOQ[1]: iocb_bio_iopoll+0x0/0x50 > [ 880.024123] RP(r2): io_do_iopoll+0xb8/0x3a4 > [ 880.024123] Backtrace: > [ 880.024123] [<1092a2b0>] io_uring_try_cancel_requests+0x184/0x3b0 > [ 880.024123] [<1092a57c>] io_ring_exit_work+0xa0/0x4c4 > [ 880.024123] [<101cb448>] process_one_work+0x1c4/0x3cc > [ 880.024123] [<101cb7d8>] worker_thread+0x188/0x4b4 > [ 880.024123] [<101d5910>] kthread+0xec/0xf4 > [ 880.024123] [<1018801c>] ret_from_kernel_thread+0x1c/0x24 See the other email, a patch for that has been in the 6.3 for a while and marked for backport. -- Jens Axboe
