On Wed, May 25, 2022 at 12:49:00PM -0700, Saravana Kannan wrote: > On Wed, May 25, 2022 at 12:12 AM Sebastian Andrzej Siewior > <bigeasy@xxxxxxxxxxxxx> wrote: > > > > On 2022-05-24 10:46:49 [-0700], Saravana Kannan wrote: > > > > Removing probe_timeout_waitqueue (as suggested) or setting the timeout > > > > to 0 avoids the delay. > > > > > > In your case, I think it might be working as intended? Curious, what > > > was the call stack in your case where it was blocked? > > > > Why is then there 10sec delay during boot? The backtrace is > > |------------[ cut here ]------------ > > |WARNING: CPU: 4 PID: 1 at drivers/base/dd.c:742 wait_for_device_probe+0x30/0x110 > > |Modules linked in: > > |CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.18.0-rc5+ #154 > > |RIP: 0010:wait_for_device_probe+0x30/0x110 > > |Call Trace: > > | <TASK> > > | prepare_namespace+0x2b/0x160 > > | kernel_init_freeable+0x2b3/0x2dd > > | kernel_init+0x11/0x110 > > | ret_from_fork+0x22/0x30 > > | </TASK> > > > > Looking closer, it can't access init. This in particular box boots > > directly the kernel without an initramfs so the kernel later mounts > > /dev/sda1 and everything is good. So that seems to be the reason… > Hello there, My (QEMU) boot times were recently extended by 10 seconds. Looking at the timestamps, it looks like nothing is being done for 10 whole seconds. A git bisect landed me at the patch in $subject: 2b28a1a84a0e ("driver core: Extend deferred probe timeout on driver registration") Adding a WARN_ON(1) in wait_for_device_probe(), as requested by the patch author from the others seeing a regression with this patch, gives two different stacktraces during boot: [ 0.459633] printk: console [netcon0] enabled [ 0.459636] printk: console [netcon0] printing thread started [ 0.459637] netconsole: network logging started [ 0.459896] cfg80211: Loading compiled-in X.509 certificates for regulatory database [ 0.460230] kworker/u8:6 (105) used greatest stack depth: 14744 bytes left [ 0.461031] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7' [ 0.461077] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2 [ 0.461085] cfg80211: failed to load regulatory.db [ 0.461113] ALSA device list: [ 0.461116] No soundcards found. [ 0.461614] ------------[ cut here ]------------ [ 0.461615] WARNING: CPU: 2 PID: 1 at drivers/base/dd.c:741 wait_for_device_probe+0x1a/0x160 [ 0.485809] Modules linked in: [ 0.486089] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.18.0-next-20220526-00004-g74f936013b08-dirty #20 [ 0.486842] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 [ 0.487707] RIP: 0010:wait_for_device_probe+0x1a/0x160 [ 0.488103] Code: 00 e8 fa e4 b5 ff 8b 44 24 04 48 83 c4 08 5b c3 0f 1f 44 00 00 53 48 83 ec 30 65 48 8b 04 25 28 00 00 00 48 89 44 24 28 31 c0 <0f> 0b e8 1f ac 57 00 8b 15 f1 b3 24 01 85 d2 75 3d 48 c7 c7 60 2f [ 0.489539] RSP: 0000:ffff9c7900013ed8 EFLAGS: 00010246 [ 0.489965] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000d02 [ 0.490597] RDX: 0000000000000cc2 RSI: 0000000000000000 RDI: 000000000002e990 [ 0.491181] RBP: 0000000000000214 R08: 000000000000000f R09: 0000000000000064 [ 0.491788] R10: ffff9c7900013c6c R11: 0000000000000000 R12: ffff8964c0343640 [ 0.492384] R13: ffffffff9e51791c R14: 0000000000000000 R15: 0000000000000000 [ 0.492960] FS: 0000000000000000(0000) GS:ffff896637d00000(0000) knlGS:0000000000000000 [ 0.493658] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.494501] CR2: 0000000000000000 CR3: 00000001ed20c001 CR4: 0000000000370ee0 [ 0.495621] Call Trace: [ 0.496059] <TASK> [ 0.496266] ? init_eaccess+0x3b/0x76 [ 0.496657] prepare_namespace+0x30/0x16a [ 0.497016] kernel_init_freeable+0x207/0x212 [ 0.497407] ? rest_init+0xc0/0xc0 [ 0.497714] kernel_init+0x16/0x120 [ 0.498250] ret_from_fork+0x1f/0x30 [ 0.498898] </TASK> [ 0.499307] ---[ end trace 0000000000000000 ]--- [ 0.748413] ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300) [ 0.749053] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) [ 0.749461] ata2.00: ATA-7: QEMU HARDDISK, version, max UDMA/100 [ 0.749470] ata2.00: 732 sectors, multi 16: LBA48 NCQ (depth 32) [ 0.749479] ata2.00: applying bridge limits [ 0.750915] ata4: SATA link down (SStatus 0 SControl 300) [ 0.752110] ata5: SATA link down (SStatus 0 SControl 300) [ 0.753424] ata6: SATA link up 1.5 Gbps (SStatus 113 SControl 300) [ 0.754877] ata3: SATA link down (SStatus 0 SControl 300) [ 0.755342] ata1.00: ATA-7: QEMU HARDDISK, version, max UDMA/100 [ 0.755377] ata1.00: 268435456 sectors, multi 16: LBA48 NCQ (depth 32) [ 0.755387] ata1.00: applying bridge limits [ 0.755486] ata6.00: ATA-7: QEMU HARDDISK, version, max UDMA/100 [ 0.755492] ata6.00: 8388608 sectors, multi 16: LBA48 NCQ (depth 32) [ 0.755500] ata6.00: applying bridge limits [ 0.757330] ata1.00: configured for UDMA/100 [ 0.757441] ata6.00: configured for UDMA/100 [ 0.757505] ata2.00: configured for UDMA/100 [ 0.758015] scsi 0:0:0:0: Direct-Access ATA QEMU HARDDISK ion PQ: 0 ANSI: 5 [ 0.760542] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 0.760669] sd 0:0:0:0: [sda] 268435456 512-byte logical blocks: (137 GB/128 GiB) [ 0.760778] sd 0:0:0:0: [sda] Write Protect is off [ 0.760787] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 0.760847] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 0.760981] sd 0:0:0:0: [sda] Preferred minimum I/O size 512 bytes [ 0.761319] scsi 1:0:0:0: Direct-Access ATA QEMU HARDDISK ion PQ: 0 ANSI: 5 [ 0.762808] sd 1:0:0:0: Attached scsi generic sg1 type 0 [ 0.763004] sd 1:0:0:0: [sdb] 732 512-byte logical blocks: (375 kB/366 KiB) [ 0.763649] sd 1:0:0:0: [sdb] Write Protect is off [ 0.763661] sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00 [ 0.763965] sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 0.764026] sd 1:0:0:0: [sdb] Preferred minimum I/O size 512 bytes [ 0.765923] scsi 5:0:0:0: Direct-Access ATA QEMU HARDDISK ion PQ: 0 ANSI: 5 [ 0.767987] sd 5:0:0:0: Attached scsi generic sg2 type 0 [ 0.768626] sd 5:0:0:0: [sdc] 8388608 512-byte logical blocks: (4.29 GB/4.00 GiB) [ 0.769909] sd 5:0:0:0: [sdc] Write Protect is off [ 0.769920] sd 5:0:0:0: [sdc] Mode Sense: 00 3a 00 00 [ 0.770515] sd 1:0:0:0: [sdb] Attached SCSI disk [ 0.770900] sd 5:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 0.771782] sd 5:0:0:0: [sdc] Preferred minimum I/O size 512 bytes [ 0.773900] sda: sda1 sda14 sda15 [ 0.774499] sd 5:0:0:0: [sdc] Attached SCSI disk [ 0.774907] sd 0:0:0:0: [sda] Attached SCSI disk [ 1.084011] input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input3 [ 10.887350] md: Waiting for all devices to be available before autodetect [ 10.887395] md: If you don't use raid, use raid=noautodetect [ 10.887445] ------------[ cut here ]------------ [ 10.887448] WARNING: CPU: 1 PID: 1 at drivers/base/dd.c:741 wait_for_device_probe+0x1a/0x160 [ 10.893987] Modules linked in: [ 10.894314] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 5.18.0-next-20220526-00004-g74f936013b08-dirty #20 [ 10.895389] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 [ 10.896590] RIP: 0010:wait_for_device_probe+0x1a/0x160 [ 10.897215] Code: 00 e8 fa e4 b5 ff 8b 44 24 04 48 83 c4 08 5b c3 0f 1f 44 00 00 53 48 83 ec 30 65 48 8b 04 25 28 00 00 00 48 89 44 24 28 31 c0 <0f> 0b e8 1f ac 57 00 8b 15 f1 b3 24 01 85 d2 75 3d 48 c7 c7 60 2f [ 10.899269] RSP: 0000:ffff9c7900013ec8 EFLAGS: 00010246 [ 10.899762] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000000 [ 10.900424] RDX: 0000000000000000 RSI: ffffffff9d998089 RDI: 00000000ffffffff [ 10.901060] RBP: 0000000000000214 R08: 80000000ffffe1ca R09: ffff9c7900013ea8 [ 10.901839] R10: 3fffffffffffffff R11: 0000000000000000 R12: ffff8964c0343640 [ 10.902615] R13: ffffffff9e51791c R14: 0000000000000000 R15: 0000000000000000 [ 10.903371] FS: 0000000000000000(0000) GS:ffff896637c80000(0000) knlGS:0000000000000000 [ 10.904188] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 10.904721] CR2: 0000000000000000 CR3: 00000001ed20c001 CR4: 0000000000370ee0 [ 10.905340] Call Trace: [ 10.905558] <TASK> [ 10.905739] md_run_setup+0x3c/0x6a [ 10.906036] prepare_namespace+0x35/0x16a [ 10.906391] kernel_init_freeable+0x207/0x212 [ 10.906748] ? rest_init+0xc0/0xc0 [ 10.907021] kernel_init+0x16/0x120 [ 10.907312] ret_from_fork+0x1f/0x30 [ 10.907617] </TASK> [ 10.907796] ---[ end trace 0000000000000000 ]--- [ 10.908159] md: Autodetecting RAID arrays. [ 10.908160] md: autorun ... [ 10.908160] md: ... autorun DONE. [ 10.911301] EXT4-fs (sda1): INFO: recovery required on readonly filesystem [ 10.911303] EXT4-fs (sda1): write access will be enabled during recovery [ 11.038001] EXT4-fs (sda1): orphan cleanup on readonly fs [ 11.038466] EXT4-fs (sda1): 2 orphan inodes deleted [ 11.038475] EXT4-fs (sda1): recovery complete [ 11.053033] EXT4-fs (sda1): mounted filesystem with ordered data mode. Quota mode: none. [ 11.053074] VFS: Mounted root (ext4 filesystem) readonly on device 8:1. [ 11.053175] devtmpfs: mounted [ 11.061921] Freeing unused kernel image (initmem) memory: 1680K [ 11.061930] Write protecting the kernel read-only data: 24576k [ 11.071108] Freeing unused kernel image (text/rodata gap) memory: 2032K [ 11.073596] Freeing unused kernel image (rodata/data gap) memory: 924K [ 11.073609] Run /sbin/init as init process Kind regards, Niklas