Re: [RFC PATCH v3 0/3] blk-cgroup: store blkcg in bio before blkcg_mutex conversion
"yu kuai" <[email protected]>
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Hi, 在 2026/8/20 14:01, Shin'ichiro Kawasaki 写道: > On Aug 18, 2026 / 15:06, Yu Kuai wrote: >> From: Yu Kuai <[email protected]> >> >> This RFC remains a preparatory series for the blkcg_mutex conversion >> proposed in the related blkcg_mutex RFC v2 series [1]. That conversion >> moves queue-local blkg topology synchronization from q->queue_lock to >> q->blkcg_mutex, which is awkward while bios directly store queue-local >> blkg references. >> >> v1 made the stored bio association queue-independent by replacing bi_blkg >> with bi_blkcg, but a bio-owned blkg reference still had to be recovered by >> looking up the bio's blkcg and current request_queue. Tao Cui reported that >> cgroup removal deletes a dying blkg from the per-blkcg radix tree before a >> throttled bio drops its reference. A later lookup for that pinned blkg then >> fails, triggers the warning in bio_pinned_blkg(), and leaks the reference. >> >> v2 makes request_queue the authoritative lookup owner before converting the >> bio association. A queue-owned rhashtable, keyed by the blkcg CSS ID, keeps >> dying blkgs discoverable until their references drain while q->blkg_list >> remains available for ordered walks. The bio conversion then stores and >> pins the blkcg CSS, lazily creates a blkg only for users which need one, and >> uses lookup-only access for completion and accounting paths which already >> own a blkg reference. Async bio punt state is finally moved from blkg to >> blkcg so punting alone does not instantiate a queue-local blkg. > FYI, a blktests-CI trial run found this patch series triggers the failure of > the test case block/027 due to "WARNING: suspicious RCU usage". I manually > confirmed that the failure is recreated in stable manner, using the kernel > at block/for-next branch tip with git hash a33221f7ab12 as the base. > > > [ 60.048652] [ T958] run blktests block/027 at 2026-08-20 14:54:34 > [ 60.342288] [ T995] sd 9:0:0:0: [sdd] Synchronizing SCSI cache > [ 60.512431] [ T998] scsi_debug:sdebug_driver_probe: scsi_debug: trim poll_queues to 0. poll_q/nr_hw = (0/4) > [ 60.514009] [ T998] scsi host10: scsi_debug: version 0191 [20210520] > dev_size_mb=8, opts=0x0, submit_queues=4, statistics=0 > [ 60.532043] [ T998] scsi 10:0:0:0: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.537838] [ T998] scsi 10:0:0:0: Power-on or device reset occurred > [ 60.546792] [ T57] sd 10:0:0:0: [sdd] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.547027] [ T998] sd 10:0:0:0: Attached scsi generic sg3 type 0 > [ 60.548204] [ T57] sd 10:0:0:0: [sdd] Write Protect is off > [ 60.550257] [ T57] sd 10:0:0:0: [sdd] Mode Sense: 73 00 10 08 > [ 60.550572] [ T57] sd 10:0:0:0: [sdd] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.552280] [ T998] scsi 10:0:0:1: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.552669] [ T57] sd 10:0:0:0: [sdd] permanent stream count = 5 > [ 60.554756] [ T57] sd 10:0:0:0: [sdd] Preferred minimum I/O size 512 bytes > [ 60.555874] [ T57] sd 10:0:0:0: [sdd] Optimal transfer size 524288 bytes > [ 60.556101] [ T998] scsi 10:0:0:1: Power-on or device reset occurred > [ 60.582832] [ T998] sd 10:0:0:1: Attached scsi generic sg4 type 0 > [ 60.586663] [ T89] sd 10:0:0:1: [sde] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.587870] [ T89] sd 10:0:0:1: [sde] Write Protect is off > [ 60.588673] [ T89] sd 10:0:0:1: [sde] Mode Sense: 73 00 10 08 > [ 60.588824] [ T89] sd 10:0:0:1: [sde] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.592560] [ T89] sd 10:0:0:1: [sde] permanent stream count = 5 > [ 60.594825] [ T89] sd 10:0:0:1: [sde] Preferred minimum I/O size 512 bytes > [ 60.596033] [ T89] sd 10:0:0:1: [sde] Optimal transfer size 524288 bytes > [ 60.601864] [ T998] scsi 10:0:0:2: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.606287] [ T57] sd 10:0:0:0: [sdd] Attached SCSI disk > [ 60.610427] [ T998] scsi 10:0:0:2: Power-on or device reset occurred > [ 60.623979] [ T998] sd 10:0:0:2: Attached scsi generic sg5 type 0 > [ 60.629219] [ T12] sd 10:0:0:2: [sdf] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.630662] [ T12] sd 10:0:0:2: [sdf] Write Protect is off > [ 60.635090] [ T12] sd 10:0:0:2: [sdf] Mode Sense: 73 00 10 08 > [ 60.635296] [ T12] sd 10:0:0:2: [sdf] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.636699] [ T998] scsi 10:0:0:3: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.638127] [ T12] sd 10:0:0:2: [sdf] permanent stream count = 5 > [ 60.640352] [ T12] sd 10:0:0:2: [sdf] Preferred minimum I/O size 512 bytes > [ 60.641526] [ T998] scsi 10:0:0:3: Power-on or device reset occurred > [ 60.642765] [ T12] sd 10:0:0:2: [sdf] Optimal transfer size 524288 bytes > [ 60.651574] [ T57] sd 10:0:0:3: [sdg] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.653359] [ T57] sd 10:0:0:3: [sdg] Write Protect is off > [ 60.654766] [ T57] sd 10:0:0:3: [sdg] Mode Sense: 73 00 10 08 > [ 60.654923] [ T57] sd 10:0:0:3: [sdg] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.656232] [ T998] sd 10:0:0:3: Attached scsi generic sg6 type 0 > [ 60.658805] [ T89] sd 10:0:0:1: [sde] Attached SCSI disk > [ 60.661190] [ T57] sd 10:0:0:3: [sdg] permanent stream count = 5 > [ 60.662705] [ T57] sd 10:0:0:3: [sdg] Preferred minimum I/O size 512 bytes > [ 60.664127] [ T57] sd 10:0:0:3: [sdg] Optimal transfer size 524288 bytes > [ 60.666666] [ T998] scsi 10:0:0:4: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.670896] [ T998] scsi 10:0:0:4: Power-on or device reset occurred > [ 60.745716] [ T998] sd 10:0:0:4: Attached scsi generic sg7 type 0 > [ 60.747518] [ T85] sd 10:0:0:4: [sdh] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.749227] [ T85] sd 10:0:0:4: [sdh] Write Protect is off > [ 60.750985] [ T85] sd 10:0:0:4: [sdh] Mode Sense: 73 00 10 08 > [ 60.751160] [ T85] sd 10:0:0:4: [sdh] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.753246] [ T85] sd 10:0:0:4: [sdh] permanent stream count = 5 > [ 60.754701] [ T85] sd 10:0:0:4: [sdh] Preferred minimum I/O size 512 bytes > [ 60.756101] [ T85] sd 10:0:0:4: [sdh] Optimal transfer size 524288 bytes > [ 60.757227] [ T998] scsi 10:0:0:5: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.759747] [ T57] sd 10:0:0:3: [sdg] Attached SCSI disk > [ 60.763568] [ T998] scsi 10:0:0:5: Power-on or device reset occurred > [ 60.787866] [ T12] sd 10:0:0:2: [sdf] Attached SCSI disk > [ 60.804506] [ T85] sd 10:0:0:4: [sdh] Attached SCSI disk > [ 60.852111] [ T998] sd 10:0:0:5: Attached scsi generic sg8 type 0 > [ 60.856376] [ T85] sd 10:0:0:5: [sdi] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.857802] [ T998] scsi 10:0:0:6: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.858071] [ T85] sd 10:0:0:5: [sdi] Write Protect is off > [ 60.861854] [ T85] sd 10:0:0:5: [sdi] Mode Sense: 73 00 10 08 > [ 60.862017] [ T85] sd 10:0:0:5: [sdi] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.862642] [ T998] scsi 10:0:0:6: Power-on or device reset occurred > [ 60.863540] [ T85] sd 10:0:0:5: [sdi] permanent stream count = 5 > [ 60.866947] [ T85] sd 10:0:0:5: [sdi] Preferred minimum I/O size 512 bytes > [ 60.870355] [ T85] sd 10:0:0:5: [sdi] Optimal transfer size 524288 bytes > [ 60.898965] [ T998] sd 10:0:0:6: Attached scsi generic sg9 type 0 > [ 60.904198] [ T12] sd 10:0:0:6: [sdj] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 60.905768] [ T12] sd 10:0:0:6: [sdj] Write Protect is off > [ 60.907526] [ T12] sd 10:0:0:6: [sdj] Mode Sense: 73 00 10 08 > [ 60.907686] [ T12] sd 10:0:0:6: [sdj] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 60.909852] [ T12] sd 10:0:0:6: [sdj] permanent stream count = 5 > [ 60.911593] [ T12] sd 10:0:0:6: [sdj] Preferred minimum I/O size 512 bytes > [ 60.912958] [ T12] sd 10:0:0:6: [sdj] Optimal transfer size 524288 bytes > [ 60.951487] [ T998] scsi 10:0:0:7: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 60.953020] [ T12] sd 10:0:0:6: [sdj] Attached SCSI disk > [ 60.961132] [ T998] scsi 10:0:0:7: Power-on or device reset occurred > [ 61.051690] [ T12] sd 10:0:0:7: [sdk] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.053835] [ T12] sd 10:0:0:7: [sdk] Write Protect is off > [ 61.055160] [ T12] sd 10:0:0:7: [sdk] Mode Sense: 73 00 10 08 > [ 61.055324] [ T12] sd 10:0:0:7: [sdk] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.060649] [ T12] sd 10:0:0:7: [sdk] permanent stream count = 5 > [ 61.062187] [ T12] sd 10:0:0:7: [sdk] Preferred minimum I/O size 512 bytes > [ 61.065148] [ T12] sd 10:0:0:7: [sdk] Optimal transfer size 524288 bytes > [ 61.101609] [ T85] sd 10:0:0:5: [sdi] Attached SCSI disk > [ 61.106279] [ T998] sd 10:0:0:7: Attached scsi generic sg10 type 0 > [ 61.114062] [ T998] scsi 10:0:0:8: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.123360] [ T998] scsi 10:0:0:8: Power-on or device reset occurred > [ 61.139984] [ T12] sd 10:0:0:7: [sdk] Attached SCSI disk > [ 61.217165] [ T89] sd 10:0:0:8: [sdl] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.219292] [ T89] sd 10:0:0:8: [sdl] Write Protect is off > [ 61.221173] [ T89] sd 10:0:0:8: [sdl] Mode Sense: 73 00 10 08 > [ 61.221335] [ T89] sd 10:0:0:8: [sdl] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.223670] [ T89] sd 10:0:0:8: [sdl] permanent stream count = 5 > [ 61.225332] [ T89] sd 10:0:0:8: [sdl] Preferred minimum I/O size 512 bytes > [ 61.226777] [ T89] sd 10:0:0:8: [sdl] Optimal transfer size 524288 bytes > [ 61.251833] [ T998] sd 10:0:0:8: Attached scsi generic sg11 type 0 > [ 61.258846] [ T998] scsi 10:0:0:9: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.266439] [ T998] scsi 10:0:0:9: Power-on or device reset occurred > [ 61.279306] [ T12] sd 10:0:0:9: [sdm] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.281013] [ T12] sd 10:0:0:9: [sdm] Write Protect is off > [ 61.282263] [ T12] sd 10:0:0:9: [sdm] Mode Sense: 73 00 10 08 > [ 61.282429] [ T12] sd 10:0:0:9: [sdm] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.283621] [ T998] sd 10:0:0:9: Attached scsi generic sg12 type 0 > [ 61.285076] [ T12] sd 10:0:0:9: [sdm] permanent stream count = 5 > [ 61.286842] [ T12] sd 10:0:0:9: [sdm] Preferred minimum I/O size 512 bytes > [ 61.288650] [ T12] sd 10:0:0:9: [sdm] Optimal transfer size 524288 bytes > [ 61.350640] [ T998] scsi 10:0:0:10: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.356467] [ T12] sd 10:0:0:9: [sdm] Attached SCSI disk > [ 61.359096] [ T998] scsi 10:0:0:10: Power-on or device reset occurred > [ 61.428598] [ T89] sd 10:0:0:8: [sdl] Attached SCSI disk > [ 61.519323] [ T998] sd 10:0:0:10: Attached scsi generic sg13 type 0 > [ 61.519455] [ T89] sd 10:0:0:10: [sdn] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.524681] [ T998] scsi 10:0:0:11: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.525872] [ T89] sd 10:0:0:10: [sdn] Write Protect is off > [ 61.530097] [ T89] sd 10:0:0:10: [sdn] Mode Sense: 73 00 10 08 > [ 61.530292] [ T89] sd 10:0:0:10: [sdn] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.530887] [ T998] scsi 10:0:0:11: Power-on or device reset occurred > [ 61.532201] [ T89] sd 10:0:0:10: [sdn] permanent stream count = 5 > [ 61.536746] [ T89] sd 10:0:0:10: [sdn] Preferred minimum I/O size 512 bytes > [ 61.539106] [ T89] sd 10:0:0:10: [sdn] Optimal transfer size 524288 bytes > [ 61.541544] [ T85] sd 10:0:0:11: [sdo] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.543209] [ T85] sd 10:0:0:11: [sdo] Write Protect is off > [ 61.545292] [ T85] sd 10:0:0:11: [sdo] Mode Sense: 73 00 10 08 > [ 61.545453] [ T85] sd 10:0:0:11: [sdo] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.547869] [ T85] sd 10:0:0:11: [sdo] permanent stream count = 5 > [ 61.550065] [ T85] sd 10:0:0:11: [sdo] Preferred minimum I/O size 512 bytes > [ 61.551491] [ T85] sd 10:0:0:11: [sdo] Optimal transfer size 524288 bytes > [ 61.560843] [ T998] sd 10:0:0:11: Attached scsi generic sg14 type 0 > [ 61.575647] [ T998] scsi 10:0:0:12: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.581203] [ T998] scsi 10:0:0:12: Power-on or device reset occurred > [ 61.659971] [ T89] sd 10:0:0:10: [sdn] Attached SCSI disk > [ 61.703691] [ T998] sd 10:0:0:12: Attached scsi generic sg15 type 0 > [ 61.714468] [ T85] sd 10:0:0:11: [sdo] Attached SCSI disk > [ 61.752593] [ T998] scsi 10:0:0:13: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.761908] [ T998] scsi 10:0:0:13: Power-on or device reset occurred > [ 61.770075] [ T89] sd 10:0:0:12: [sdp] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.771727] [ T89] sd 10:0:0:12: [sdp] Write Protect is off > [ 61.773108] [ T89] sd 10:0:0:12: [sdp] Mode Sense: 73 00 10 08 > [ 61.773266] [ T89] sd 10:0:0:12: [sdp] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.775657] [ T89] sd 10:0:0:12: [sdp] permanent stream count = 5 > [ 61.778651] [ T89] sd 10:0:0:12: [sdp] Preferred minimum I/O size 512 bytes > [ 61.781598] [ T89] sd 10:0:0:12: [sdp] Optimal transfer size 524288 bytes > [ 61.801054] [ T85] sd 10:0:0:13: [sdq] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.802968] [ T85] sd 10:0:0:13: [sdq] Write Protect is off > [ 61.804603] [ T85] sd 10:0:0:13: [sdq] Mode Sense: 73 00 10 08 > [ 61.804798] [ T85] sd 10:0:0:13: [sdq] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.809291] [ T85] sd 10:0:0:13: [sdq] permanent stream count = 5 > [ 61.812234] [ T85] sd 10:0:0:13: [sdq] Preferred minimum I/O size 512 bytes > [ 61.814067] [ T85] sd 10:0:0:13: [sdq] Optimal transfer size 524288 bytes > [ 61.856311] [ T998] sd 10:0:0:13: Attached scsi generic sg16 type 0 > [ 61.872980] [ T998] scsi 10:0:0:14: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.880018] [ T998] scsi 10:0:0:14: Power-on or device reset occurred > [ 61.898152] [ T12] sd 10:0:0:14: [sdr] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 61.901297] [ T12] sd 10:0:0:14: [sdr] Write Protect is off > [ 61.904599] [ T12] sd 10:0:0:14: [sdr] Mode Sense: 73 00 10 08 > [ 61.904758] [ T12] sd 10:0:0:14: [sdr] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 61.907952] [ T12] sd 10:0:0:14: [sdr] permanent stream count = 5 > [ 61.909473] [ T12] sd 10:0:0:14: [sdr] Preferred minimum I/O size 512 bytes > [ 61.911556] [ T12] sd 10:0:0:14: [sdr] Optimal transfer size 524288 bytes > [ 61.921187] [ T89] sd 10:0:0:12: [sdp] Attached SCSI disk > [ 61.947703] [ T998] sd 10:0:0:14: Attached scsi generic sg17 type 0 > [ 61.956937] [ T998] scsi 10:0:0:15: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 61.964139] [ T998] scsi 10:0:0:15: Power-on or device reset occurred > [ 61.966101] [ T85] sd 10:0:0:13: [sdq] Attached SCSI disk > [ 62.054834] [ T998] sd 10:0:0:15: Attached scsi generic sg18 type 0 > [ 62.063562] [ T998] scsi 10:0:0:16: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 62.069436] [ T998] scsi 10:0:0:16: Power-on or device reset occurred > [ 62.070705] [ T89] sd 10:0:0:15: [sds] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 62.073325] [ T89] sd 10:0:0:15: [sds] Write Protect is off > [ 62.074520] [ T89] sd 10:0:0:15: [sds] Mode Sense: 73 00 10 08 > [ 62.074682] [ T89] sd 10:0:0:15: [sds] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 62.078365] [ T85] sd 10:0:0:16: [sdt] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 62.079508] [ T89] sd 10:0:0:15: [sds] permanent stream count = 5 > [ 62.080108] [ T85] sd 10:0:0:16: [sdt] Write Protect is off > [ 62.080978] [ T89] sd 10:0:0:15: [sds] Preferred minimum I/O size 512 bytes > [ 62.082994] [ T85] sd 10:0:0:16: [sdt] Mode Sense: 73 00 10 08 > [ 62.083665] [ T89] sd 10:0:0:15: [sds] Optimal transfer size 524288 bytes > [ 62.084433] [ T998] sd 10:0:0:16: Attached scsi generic sg19 type 0 > [ 62.086905] [ T85] sd 10:0:0:16: [sdt] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 62.090249] [ T85] sd 10:0:0:16: [sdt] permanent stream count = 5 > [ 62.091796] [ T85] sd 10:0:0:16: [sdt] Preferred minimum I/O size 512 bytes > [ 62.095042] [ T998] scsi 10:0:0:17: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 62.096731] [ T85] sd 10:0:0:16: [sdt] Optimal transfer size 524288 bytes > [ 62.099216] [ T12] sd 10:0:0:14: [sdr] Attached SCSI disk > [ 62.102505] [ T998] scsi 10:0:0:17: Power-on or device reset occurred > [ 62.130600] [ T89] sd 10:0:0:15: [sds] Attached SCSI disk > [ 62.152860] [ T57] sd 10:0:0:17: [sdu] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 62.154661] [ T57] sd 10:0:0:17: [sdu] Write Protect is off > [ 62.156840] [ T57] sd 10:0:0:17: [sdu] Mode Sense: 73 00 10 08 > [ 62.156999] [ T57] sd 10:0:0:17: [sdu] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 62.158980] [ T57] sd 10:0:0:17: [sdu] permanent stream count = 5 > [ 62.160461] [ T57] sd 10:0:0:17: [sdu] Preferred minimum I/O size 512 bytes > [ 62.161941] [ T57] sd 10:0:0:17: [sdu] Optimal transfer size 524288 bytes > [ 62.197490] [ T998] sd 10:0:0:17: Attached scsi generic sg20 type 0 > [ 62.202924] [ T85] sd 10:0:0:16: [sdt] Attached SCSI disk > [ 62.246749] [ T998] scsi 10:0:0:18: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 62.253160] [ T998] scsi 10:0:0:18: Power-on or device reset occurred > [ 62.362859] [ T85] sd 10:0:0:18: [sdv] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 62.364530] [ T85] sd 10:0:0:18: [sdv] Write Protect is off > [ 62.369860] [ T85] sd 10:0:0:18: [sdv] Mode Sense: 73 00 10 08 > [ 62.370019] [ T85] sd 10:0:0:18: [sdv] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 62.372485] [ T85] sd 10:0:0:18: [sdv] permanent stream count = 5 > [ 62.375392] [ T85] sd 10:0:0:18: [sdv] Preferred minimum I/O size 512 bytes > [ 62.377326] [ T85] sd 10:0:0:18: [sdv] Optimal transfer size 524288 bytes > [ 62.386677] [ T998] sd 10:0:0:18: Attached scsi generic sg21 type 0 > [ 62.390025] [ T57] sd 10:0:0:17: [sdu] Attached SCSI disk > [ 62.395147] [ T998] scsi 10:0:0:19: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 62.400566] [ T998] scsi 10:0:0:19: Power-on or device reset occurred > [ 62.492252] [ T998] sd 10:0:0:19: Attached scsi generic sg22 type 0 > [ 62.504374] [ T89] sd 10:0:0:19: [sdw] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 62.506027] [ T89] sd 10:0:0:19: [sdw] Write Protect is off > [ 62.507260] [ T89] sd 10:0:0:19: [sdw] Mode Sense: 73 00 10 08 > [ 62.507422] [ T89] sd 10:0:0:19: [sdw] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 62.509393] [ T89] sd 10:0:0:19: [sdw] permanent stream count = 5 > [ 62.512301] [ T89] sd 10:0:0:19: [sdw] Preferred minimum I/O size 512 bytes > [ 62.513697] [ T89] sd 10:0:0:19: [sdw] Optimal transfer size 524288 bytes > [ 62.541424] [ T998] scsi 10:0:0:20: Direct-Access Linux scsi_debug 0191 PQ: 0 ANSI: 7 > [ 62.552224] [ T998] scsi 10:0:0:20: Power-on or device reset occurred > [ 62.599822] [ T85] sd 10:0:0:18: [sdv] Attached SCSI disk > [ 62.609329] [ T57] sd 10:0:0:20: [sdx] 268435456 512-byte logical blocks: (137 GB/128 GiB) > [ 62.613381] [ T57] sd 10:0:0:20: [sdx] Write Protect is off > [ 62.618693] [ T57] sd 10:0:0:20: [sdx] Mode Sense: 73 00 10 08 > [ 62.618850] [ T57] sd 10:0:0:20: [sdx] Write cache: enabled, read cache: enabled, supports DPO and FUA > [ 62.621631] [ T57] sd 10:0:0:20: [sdx] permanent stream count = 5 > [ 62.623343] [ T57] sd 10:0:0:20: [sdx] Preferred minimum I/O size 512 bytes > [ 62.624997] [ T57] sd 10:0:0:20: [sdx] Optimal transfer size 524288 bytes > [ 62.628524] [ T998] sd 10:0:0:20: Attached scsi generic sg23 type 0 > [ 62.643270] [ T89] sd 10:0:0:19: [sdw] Attached SCSI disk > [ 62.726714] [ T57] sd 10:0:0:20: [sdx] Attached SCSI disk > [ 71.628857] [ T958] sd 10:0:0:0: [sdd] Synchronizing SCSI cache > > [ 71.725933] [ T1258] ============================= > [ 71.727013] [ T1258] WARNING: suspicious RCU usage > [ 71.728048] [ T1258] 7.2.0-rc5+ #448 Not tainted > [ 71.729043] [ T1258] ----------------------------- > [ 71.730053] [ T1258] block/blk-cgroup.h:273 blkg_lookup_any() requires an RCU read lock! > [ 71.731460] [ T1258] > other info that might help us debug this: > > [ 71.734042] [ T1258] > rcu_scheduler_active = 2, debug_locks = 1 > [ 71.735857] [ T1258] 1 lock held by fio/1258: > [ 71.736805] [ T1258] #0: ffff88810a4bb6c8 (&q->queue_lock){..-.}-{3:3}, at: bio_blkg+0x131/0xed0 > [ 71.738307] [ T1258] > stack backtrace: > [ 71.739882] [ T1258] CPU: 0 UID: 0 PID: 1258 Comm: fio Not tainted 7.2.0-rc5+ #448 PREEMPT(full) > [ 71.739886] [ T1258] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-10.fc44 06/10/2025 > [ 71.739890] [ T1258] Call Trace: > [ 71.739892] [ T1258] <TASK> > [ 71.739894] [ T1258] dump_stack_lvl+0x6a/0x90 > [ 71.739900] [ T1258] lockdep_rcu_suspicious.cold+0x3a/0x7d > [ 71.739906] [ T1258] blkg_lookup_any+0x3ad/0x5d0 > [ 71.739910] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.739915] [ T1258] ? bio_blkg+0x634/0xed0 > [ 71.739917] [ T1258] ? lock_release+0x1b5/0x340 > [ 71.739922] [ T1258] bio_blkg+0x681/0xed0 > [ 71.739930] [ T1258] bfq_insert_requests+0x17cc/0x8f90 Thanks for the test! This is not a real problem, in this path spin_lock is held so rcu lock is not necessary. I'll add additional rcu lock in this path, because the spin_lock will be removed in the future. > [ 71.739937] [ T1258] ? __create_object+0x4e/0xe0 > [ 71.739941] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.739945] [ T1258] ? __create_object+0x78/0xe0 > [ 71.739947] [ T1258] ? lock_release+0x1b5/0x340 > [ 71.739952] [ T1258] ? _raw_spin_unlock_irqrestore+0x35/0x60 > [ 71.739956] [ T1258] ? __pfx_bfq_insert_requests+0x10/0x10 > [ 71.739959] [ T1258] ? rcu_is_watching+0x11/0xb0 > [ 71.739963] [ T1258] ? kmem_cache_alloc_noprof+0x4bf/0x6d0 > [ 71.739967] [ T1258] ? radix_tree_node_alloc.constprop.0+0x19e/0x3a0 > [ 71.739973] [ T1258] ? radix_tree_node_alloc.constprop.0+0x19e/0x3a0 > [ 71.739978] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.739982] [ T1258] ? ioc_find_get_icq+0x585/0xab0 > [ 71.739985] [ T1258] ? lock_release+0x1b5/0x340 > [ 71.739987] [ T1258] ? trace_hardirqs_on+0x14/0x190 > [ 71.739991] [ T1258] ? ioc_find_get_icq+0x594/0xab0 > [ 71.739997] [ T1258] ? bdev_count_inflight_rw.part.0+0x17f/0x320 > [ 71.740005] [ T1258] ? bdev_count_inflight+0x67/0xa0 > [ 71.740008] [ T1258] ? __pfx_bdev_count_inflight+0x10/0x10 > [ 71.740012] [ T1258] ? ktime_get+0x27/0x210 > [ 71.740016] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.740021] [ T1258] blk_mq_insert_request+0x248/0xbe0 > [ 71.740025] [ T1258] ? __pfx_blk_mq_insert_request+0x10/0x10 > [ 71.740027] [ T1258] ? kvm_clock_get_cycles+0x14/0x30 > [ 71.740036] [ T1258] blk_mq_submit_bio+0xf25/0x2a00 > [ 71.740040] [ T1258] ? bio_associate_blkcg_from_css+0x14b/0x670 > [ 71.740044] [ T1258] ? __pfx_blk_mq_submit_bio+0x10/0x10 > [ 71.740047] [ T1258] ? iov_iter_extract_bvecs+0x50f/0xb30 > [ 71.740054] [ T1258] ? __pfx_blk_cgroup_bio_start+0x10/0x10 > [ 71.740060] [ T1258] submit_bio_noacct_nocheck+0x41d/0xb00 > [ 71.740066] [ T1258] ? __pfx_submit_bio_noacct_nocheck+0x10/0x10 > [ 71.740071] [ T1258] ? submit_bio_noacct+0x80c/0x2070 > [ 71.740078] [ T1258] blkdev_direct_IO+0x949/0x1f90 > [ 71.740080] [ T1258] ? lock_acquire+0x199/0x320 > [ 71.740083] [ T1258] ? is_bpf_text_address+0x1d/0xf0 > [ 71.740086] [ T1258] ? lock_acquire+0x1a9/0x320 > [ 71.740088] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.740092] [ T1258] ? is_bpf_text_address+0x60/0xf0 > [ 71.740094] [ T1258] ? lock_release+0x1b5/0x340 > [ 71.740099] [ T1258] ? __pfx_blkdev_direct_IO+0x10/0x10 > [ 71.740102] [ T1258] ? __kernel_text_address+0xe/0x30 > [ 71.740105] [ T1258] ? __pfx_stack_trace_consume_entry+0x10/0x10 > [ 71.740108] [ T1258] ? unwind_get_return_address+0x67/0xd0 > [ 71.740111] [ T1258] ? arch_stack_walk+0xef/0x140 > [ 71.740116] [ T1258] ? selinux_file_permission+0x3c0/0x530 > [ 71.740122] [ T1258] blkdev_read_iter+0x223/0x440 > [ 71.740128] [ T1258] aio_read+0x2e8/0x5b0 > [ 71.740133] [ T1258] ? __pfx_aio_read+0x10/0x10 > [ 71.740148] [ T1258] ? __pfx___might_resched+0x10/0x10 > [ 71.740151] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.740155] [ T1258] ? __might_fault+0x97/0x140 > [ 71.740160] [ T1258] ? io_submit_one+0x440/0x1a70 > [ 71.740162] [ T1258] io_submit_one+0x440/0x1a70 > [ 71.740171] [ T1258] ? __pfx_io_submit_one+0x10/0x10 > [ 71.740173] [ T1258] ? rcu_is_watching+0x11/0xb0 > [ 71.740182] [ T1258] ? __pfx___might_resched+0x10/0x10 > [ 71.740184] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.740191] [ T1258] ? __x64_sys_io_submit+0x193/0x2f0 > [ 71.740194] [ T1258] __x64_sys_io_submit+0x193/0x2f0 > [ 71.740198] [ T1258] ? __pfx___x64_sys_io_submit+0x10/0x10 > [ 71.740203] [ T1258] ? lock_release+0x1b5/0x340 > [ 71.740211] [ T1258] do_syscall_64+0xdf/0x790 > [ 71.740218] [ T1258] ? __lock_acquire+0x3d2/0x2440 > [ 71.740222] [ T1258] ? __pfx___css_rstat_updated+0x10/0x10 > [ 71.740228] [ T1258] ? lock_acquire+0x199/0x320 > [ 71.740230] [ T1258] ? count_memcg_events_mm.constprop.0+0x22/0x130 > [ 71.740233] [ T1258] ? rcu_is_watching+0x11/0xb0 > [ 71.740236] [ T1258] ? count_memcg_events+0x107/0x4c0 > [ 71.740238] [ T1258] ? find_held_lock+0x2b/0x80 > [ 71.740242] [ T1258] ? rcu_is_watching+0x11/0xb0 > [ 71.740245] [ T1258] ? __up_read+0x351/0x9c0 > [ 71.740249] [ T1258] ? __pfx___up_read+0x10/0x10 > [ 71.740252] [ T1258] ? do_user_addr_fault+0x28c/0xaf0 > [ 71.740255] [ T1258] ? lock_release+0x1b5/0x340 > [ 71.740260] [ T1258] ? rcu_is_watching+0x11/0xb0 > [ 71.740263] [ T1258] ? trace_hardirqs_on+0x14/0x190 > [ 71.740265] [ T1258] ? preempt_count_add+0x7f/0x190 > [ 71.740267] [ T1258] ? do_syscall_64+0x5d/0x790 > [ 71.740270] [ T1258] ? do_syscall_64+0x8d/0x790 > [ 71.740272] [ T1258] ? irqentry_exit+0xfc/0x810 > [ 71.740277] [ T1258] entry_SYSCALL_64_after_hwframe+0x76/0x7e > [ 71.740280] [ T1258] RIP: 0033:0x7f40f240c0cd > [ 71.740283] [ T1258] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 03 4d 0f 00 f7 d8 64 89 01 48 > [ 71.740285] [ T1258] RSP: 002b:00007fff410d1b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 > [ 71.740290] [ T1258] RAX: ffffffffffffffda RBX: 00007f40f2316718 RCX: 00007f40f240c0cd > [ 71.740292] [ T1258] RDX: 000000001f5f9750 RSI: 0000000000000001 RDI: 00007f40e3fdf000 > [ 71.740293] [ T1258] RBP: 00007fff410d1b40 R08: 000000001f7094e0 R09: 000000001f709400 > [ 71.740294] [ T1258] R10: 000000001f709400 R11: 0000000000000246 R12: 00007f40e3fdf000 > [ 71.740296] [ T1258] R13: 0000000000000000 R14: 000000001f5f9750 R15: 0000000000000001 > [ 71.740305] [ T1258] </TASK> > [ 73.210606] [ T958] sd 10:0:0:1: [sde] Synchronizing SCSI cache > [ 73.251578] [ T296] device offline error, dev sdn, sector 189403096 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256114] [ T296] device offline error, dev sdn, sector 199421272 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256143] [ T296] device offline error, dev sdn, sector 203643552 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256162] [ T296] device offline error, dev sdn, sector 207427136 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256201] [ T296] device offline error, dev sdn, sector 214836224 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256219] [ T296] device offline error, dev sdn, sector 235862656 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256237] [ T296] device offline error, dev sdn, sector 236401976 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256272] [ T296] device offline error, dev sdn, sector 238514280 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256290] [ T296] device offline error, dev sdn, sector 245902744 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 73.256308] [ T296] device offline error, dev sdn, sector 246183280 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 74.011940] [ T958] sd 10:0:0:10: [sdn] Synchronizing SCSI cache > [ 74.448759] [ T958] sd 10:0:0:11: [sdo] Synchronizing SCSI cache > [ 74.839748] [ T958] sd 10:0:0:12: [sdp] Synchronizing SCSI cache > [ 75.265115] [ T958] sd 10:0:0:13: [sdq] Synchronizing SCSI cache > [ 75.660906] [ T958] sd 10:0:0:14: [sdr] Synchronizing SCSI cache > [ 76.010466] [ T958] sd 10:0:0:15: [sds] Synchronizing SCSI cache > [ 76.426481] [ T958] sd 10:0:0:16: [sdt] Synchronizing SCSI cache > [ 76.871466] [ T958] sd 10:0:0:17: [sdu] Synchronizing SCSI cache > [ 77.286379] [ T958] sd 10:0:0:18: [sdv] Synchronizing SCSI cache > [ 77.844417] [ T958] sd 10:0:0:19: [sdw] Synchronizing SCSI cache > [ 78.325753] [ T958] sd 10:0:0:2: [sdf] Synchronizing SCSI cache > [ 78.331587] [ T1336] blk_print_req_error: 225 callbacks suppressed > [ 78.331594] [ T1336] device offline error, dev sdx, sector 129278536 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 78.334828] [ T1336] device offline error, dev sdx, sector 23920864 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 78.687509] [ T958] sd 10:0:0:20: [sdx] Synchronizing SCSI cache > [ 78.695490] [ T332] device offline error, dev sdg, sector 200011456 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 78.697842] [ T332] device offline error, dev sdg, sector 80898080 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 78.700331] [ T332] device offline error, dev sdg, sector 31089776 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 78.701066] [ T107] device offline error, dev sdg, sector 107919016 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 79.057557] [ T958] sd 10:0:0:3: [sdg] Synchronizing SCSI cache > [ 79.506572] [ T958] sd 10:0:0:4: [sdh] Synchronizing SCSI cache > [ 79.516857] [ T106] device offline error, dev sdi, sector 118581624 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 79.517079] [ T332] device offline error, dev sdi, sector 88640592 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 79.518274] [ T106] device offline error, dev sdi, sector 124905824 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 79.519554] [ T332] device offline error, dev sdi, sector 102957264 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 > [ 80.013799] [ T958] sd 10:0:0:5: [sdi] Synchronizing SCSI cache > [ 80.364040] [ T958] sd 10:0:0:6: [sdj] Synchronizing SCSI cache > [ 80.737957] [ T958] sd 10:0:0:7: [sdk] Synchronizing SCSI cache > [ 81.150826] [ T958] sd 10:0:0:8: [sdl] Synchronizing SCSI cache > [ 81.468618] [ T958] sd 10:0:0:9: [sdm] Synchronizing SCSI cache -- Thanks, Kuai