Performing verification for noble. Firstly, I started with 6.8.0-57-generic with the following commit reverted:
commit ab99a87542f194f28e2364a42afbf9fb48b1c724 Author: Ofir Gal <ofir....@volumez.com> Date: Fri Jun 7 10:27:44 2024 +0300 Subject: md/md-bitmap: fix writing non bitmap pages Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab99a87542f194f28e2364a42afbf9fb48b1c724 This is because the testcases are the same, as the above bug was fixed due to this bug existing in the first place. I ran the reproducer: sudo[1591]: mruffell : TTY=pts/0 ; PWD=/home/mruffell/blktests ; USER=root ; COMMAND=./check md/001 sudo[1591]: pam_unix(sudo:session): session opened for user root(uid=0) by mruffell(uid=1003) unknown: run blktests md/001 at 2025-04-07 03:19:12 root[1627]: run blktests md/001 kernel: brd: module loaded (udev-worker)[1632]: dm-0: Process '/usr/bin/unshare -m /usr/bin/snap auto-import --mount=/dev/dm-0' failed with exit code 1. kernel: Key type psk registered kernel: nvmet: adding nsid 1 to subsystem blktests-subsystem-1 kernel: nvmet_tcp: enabling port 0 (127.0.0.1:4420) kernel: nvmet: creating nvm controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349. kernel: nvme nvme1: creating 2 I/O queues. kernel: nvme nvme1: mapped 2/0/0 default/read/poll queues. kernel: nvme nvme1: new ctrl: NQN "blktests-subsystem-1", addr 127.0.0.1:4420, hostnqn: nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349 (udev-worker)[1632]: nvme1n1: Process '/usr/bin/unshare -m /usr/bin/snap auto-import --mount=/dev/nvme1n1' failed with exit code 1. (udev-worker)[1632]: md127: Process '/usr/bin/unshare -m /usr/bin/snap auto-import --mount=/dev/md127' failed with exit code 1. kernel: md/raid1:md127: active with 1 out of 2 mirrors kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 1 PID: 58 at net/core/skbuff.c:7006 skb_splice_from_iter+0x139/0x370 kernel: Modules linked in: nvme_tcp nvmet_tcp nvmet nvme_keyring brd raid1 tls cfg80211 8021q garp mrp stp llc binfmt_misc nls_iso8859_1 intel_rapl_msr intel_rapl_common intel_uncore_frequency_common isst_if_common skx_edac_common nfit crct10dif_pclmul crc32_pclmul polyval_clmulni polyval_generic ghash_clmulni_intel sha256_ssse3 sha1_ssse3 aesni_intel crypto_simd cryptd rapl psmouse nvme pvpanic_mmio pvpanic i2c_piix4 input_leds mac_hid serio_raw sch_fq_codel dm_multipath nvme_fabrics nvme_core nvme_auth efi_pstore nfnetlink dmi_sysfs virtio_rng ip_tables x_tables autofs4 kernel: CPU: 1 PID: 58 Comm: kworker/1:1H Not tainted 6.8.0-57-generic #52+TEST404844v20250402b1-Ubuntu kernel: Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 kernel: Workqueue: nvme_tcp_wq nvme_tcp_io_work [nvme_tcp] kernel: RIP: 0010:skb_splice_from_iter+0x139/0x370 kernel: Code: 39 e1 48 8b 53 08 49 0f 47 cc 49 89 cd f6 c2 01 0f 85 c0 01 00 00 66 90 48 89 da 48 8b 12 80 e6 08 0f 84 8e 00 00 00 4d 89 fe <0f> 0b 49 c7 c0 fb ff ff ff 48 8b 85 68 ff ff ff 41 01 46 70 41 01 kernel: RSP: 0018:ffffb1e9401fba38 EFLAGS: 00010246 kernel: RAX: 0000000000000000 RBX: ffffe43105245700 RCX: 00000000000009e8 kernel: RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 kernel: RBP: ffffb1e9401fbae0 R08: 0000000000000000 R09: 0000000000000000 kernel: R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000009e8 kernel: R13: 00000000000009e8 R14: ffff97c745626c00 R15: ffff97c745626c00 kernel: FS: 0000000000000000(0000) GS:ffff97c877d00000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 00005d8c3063bd20 CR3: 0000000110f88003 CR4: 00000000003706f0 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 kernel: Call Trace: kernel: <TASK> kernel: ? show_regs+0x6d/0x80 kernel: ? __warn+0x89/0x160 kernel: ? skb_splice_from_iter+0x139/0x370 kernel: ? report_bug+0x17e/0x1b0 kernel: ? handle_bug+0x51/0xa0 kernel: ? exc_invalid_op+0x18/0x80 kernel: ? asm_exc_invalid_op+0x1b/0x20 kernel: ? skb_splice_from_iter+0x139/0x370 kernel: ? skb_splice_from_iter+0xd5/0x370 kernel: tcp_sendmsg_locked+0x352/0xd70 kernel: ? tcp_push+0x159/0x190 kernel: ? tcp_sendmsg_locked+0x9c4/0xd70 kernel: tcp_sendmsg+0x2c/0x50 kernel: inet_sendmsg+0x42/0x80 kernel: sock_sendmsg+0x118/0x150 kernel: nvme_tcp_try_send_data+0x16e/0x4d0 [nvme_tcp] kernel: nvme_tcp_try_send+0x23c/0x300 [nvme_tcp] kernel: nvme_tcp_io_work+0x40/0xe0 [nvme_tcp] kernel: process_one_work+0x175/0x350 kernel: worker_thread+0x306/0x440 kernel: ? _raw_spin_unlock_irqrestore+0x11/0x60 kernel: ? __pfx_worker_thread+0x10/0x10 kernel: kthread+0xef/0x120 kernel: ? __pfx_kthread+0x10/0x10 kernel: ret_from_fork+0x44/0x70 kernel: ? __pfx_kthread+0x10/0x10 kernel: ret_from_fork_asm+0x1b/0x30 kernel: </TASK> kernel: ---[ end trace 0000000000000000 ]--- Okay, we can reproduce the issue. I then enabled -proposed, and installed 6.8.0-58-generic, note, which contains: commit ab99a87542f194f28e2364a42afbf9fb48b1c724 Author: Ofir Gal <ofir....@volumez.com> Date: Fri Jun 7 10:27:44 2024 +0300 Subject: md/md-bitmap: fix writing non bitmap pages Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab99a87542f194f28e2364a42afbf9fb48b1c724 AND the three fixed we are testing: commit 23a55f4492fcf868d068da31a2cd30c15f46207d Author: Ofir Gal <ofir....@volumez.com> Date: Thu Jul 18 11:45:12 2024 +0300 Subject: net: introduce helper sendpages_ok() Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23a55f4492fcf868d068da31a2cd30c15f46207d commit 6af7331a70b4888df43ec1d7e1803ae2c43b6981 Author: Ofir Gal <ofir....@volumez.com> Date: Thu Jul 18 11:45:13 2024 +0300 Subject: nvme-tcp: use sendpages_ok() instead of sendpage_ok() Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6af7331a70b4888df43ec1d7e1803ae2c43b6981 commit 7960af373ade3b39e10106ef415e43a1d2aa48c6 Author: Ofir Gal <ofir....@volumez.com> Date: Thu Jul 18 11:45:14 2024 +0300 Subject: drbd: use sendpages_ok() instead of sendpage_ok() Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7960af373ade3b39e10106ef415e43a1d2aa48c6 I rebooted and ran the reproducer: $ uname -rv 6.8.0-58-generic #60-Ubuntu SMP PREEMPT_DYNAMIC Fri Mar 14 18:29:48 UTC 2025 $ sudo ./check md/001 md/001 (Raid with bitmap on tcp nvmet with opt-io-size over bitmap size) [passed] runtime ... 0.452s Just to make sure that the three commits really did fix the issue, I then built and booted into 6.8.0-58-generic, again with commit ab99a87542f194f28e2364a42afbf9fb48b1c724 Author: Ofir Gal <ofir....@volumez.com> Date: Fri Jun 7 10:27:44 2024 +0300 Subject: md/md-bitmap: fix writing non bitmap pages Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab99a87542f194f28e2364a42afbf9fb48b1c724 reverted, so we just test the new fixes only. $ uname -rv 6.8.0-58-generic #60+TEST404844v20250328b1-Ubuntu SMP PREEMPT_DYNAMIC Fri Mar 28 $ cd blktests/ $ sudo ./check md/001 md/001 (Raid with bitmap on tcp nvmet with opt-io-size over bitmap size) [passed] runtime 0.452s ... 0.445 We continue to pass with the new patches only. The kernel in -proposed fixes the issue, happy to mark verified for noble. ** Tags removed: verification-needed-noble-linux ** Tags added: verification-done-noble-linux -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2093871 Title: Introduce and use sendpages_ok() instead of sendpage_ok() in nvme-tcp and drbd Status in linux package in Ubuntu: Fix Released Status in linux source package in Noble: Fix Committed Status in linux source package in Oracular: Fix Committed Bug description: BugLink: https://bugs.launchpad.net/bugs/2093871 [Impact] Currently the nvme-tcp and drbd subsystems try to enable the MSG_SPLICE_PAGES flag on pages to be written, and when MSG_SPLICE_PAGES is set, eventually it calls skb_splice_from_iter(), which then checks all pages with sendpage_ok() to see if all the pages are sendable. At the moment, both subsystems only check the first page in a potentially contiguous block of pages, if they are sendpage_ok(), and if the first page is, then it just assumes all the rest are sendpage_ok() too, and sends the I/O off to eventually be found out by skb_splice_from_iter(). If one or more of the pages in the contiguous block is not sendpage_ok(), then we get a warn printed, data transfer is aborted. In the nvme-tcp case, IO then hangs. This patchset introduces sendpages_ok() which iterates over each page in a contiguous block, checks if it is sendpage_ok(), and only returns true if all of them are. This resolves the whole MSG_SPLICE_PAGES flag situation, since you can now depend on the result of sendpages_ok(), instead of just assuming everything is okay. This issue is what caused bug 2075110 [0] to be discovered in the first place, since it was responsible for contigious blocks of pages where the first was sendpage_ok(), but pages further into the block were not. [0] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2075110 Even with "md/md-bitmap: fix writing non bitmap pages" applied, the issue can still happen, e.g. with merged IO pages, so this fix is still needed to eliminate the issue. [Fix] The fixes landed in mainline 6.12-rc1: commit 23a55f4492fcf868d068da31a2cd30c15f46207d Author: Ofir Gal <ofir....@volumez.com> Date: Thu Jul 18 11:45:12 2024 +0300 Subject: net: introduce helper sendpages_ok() Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23a55f4492fcf868d068da31a2cd30c15f46207d commit 6af7331a70b4888df43ec1d7e1803ae2c43b6981 Author: Ofir Gal <ofir....@volumez.com> Date: Thu Jul 18 11:45:13 2024 +0300 Subject: nvme-tcp: use sendpages_ok() instead of sendpage_ok() Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6af7331a70b4888df43ec1d7e1803ae2c43b6981 commit 7960af373ade3b39e10106ef415e43a1d2aa48c6 Author: Ofir Gal <ofir....@volumez.com> Date: Thu Jul 18 11:45:14 2024 +0300 Subject: drbd: use sendpages_ok() instead of sendpage_ok() Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7960af373ade3b39e10106ef415e43a1d2aa48c6 They are needed for noble and oracular. [Testcase] This is the same testcase as the original bug 2075110 [0], as the fix is designed to prevent it or similar other bugs from happening again. [0] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2075110 Because of this, the fix: commit ab99a87542f194f28e2364a42afbf9fb48b1c724 Author: Ofir Gal <ofir....@volumez.com> Date: Fri Jun 7 10:27:44 2024 +0300 Subject: md/md-bitmap: fix writing non bitmap pages Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab99a87542f194f28e2364a42afbf9fb48b1c724 needs to be reverted during your test runs, or you won't see the issue reproduce. You can use this ppa for updated kernels with the revert to trigger the issue: https://launchpad.net/~mruffell/+archive/ubuntu/sf404844-revert This can be reproduced by running blktests md/001 [1], which the author of the fix created to act as a regression test for this issue. [1] https://github.com/osandov/blktests/commit/a24a7b462816fbad7dc6c175e53fcc764ad0a822 Deploy a fresh Noble VM, that has a scratch NVME disk. $ sudo apt install build-essential fio $ git clone https://github.com/osandov/blktests.git $ cd blktests $ make $ echo "TEST_DEVS=(/dev/nvme0n1)" > config $ sudo ./check md/001 The md/001 test will hang an affected system, and the above oops message will be visible in dmesg. A test kernel is available in the following ppa: https://launchpad.net/~mruffell/+archive/ubuntu/sf404844-test This has both the fixes for this bug, and also bug 2075110. The issue will not reproduce. There is also a test kernel available with the fix for this bug present, and the fix for bug 2075110 reverted, so you can see the impact of these patches only: https://launchpad.net/~mruffell/+archive/ubuntu/sf404844-repro This will also not reproduce the issue anymore. [Where problems could occur] What we are changing is rather simple. Instead of checking the first page and assuming all the rest in the contiguous block are sendpage_ok(), we now check each page in the contiguous block to see if all of them are sendpage_ok(). If any aren't, then we abort the write to the driver, and try again later. This saves us time. However, it does take longer to call sendpage_ok() on each of the pages in the contiguous block, so there will be a minor performance hit. Small performance hit for correctness should be okay. Currently we are only applying to nvme-tcp and drbd subsystems. If a regression were to occur, it would affect users of those subsystems only. [Other info] Upstream mailing list: https://lore.kernel.org/all/20240718084515.3833733-1-ofir....@volumez.com/T/#u To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2093871/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
