[Bug 1169932] New: losetup --partscan won't create partition devices
http://bugzilla.suse.com/show_bug.cgi?id=1169932 Bug ID: 1169932 Summary: losetup --partscan won't create partition devices Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-maintainers@forge.provo.novell.com Reporter: mkoutny@suse.com QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- ## Environment kernel-default-5.7.rc1-1.1.g84ddad4.x86_64 systemd-244-3.1.x86_64 util-linux-2.35.1-1.1.x86_64 ## Expected behavior image.0.raw is a whole dist image file # losetup --find --show --partscan ~/image.0.raw would created devices for the image plus the partitions /dev/loop0 /dev/loop0p1 /dev/loop0p2 ## Actual behavior # losetup --find --show --partscan ~/image.0.raw creates only the top device /dev/loop0
Apr 20 16:54:30 blackbook kernel: loop_reread_partitions: partition scan of loop2 (/home/mkoutny/image.0.raw) failed (rc=-16)
## Observation - this started happening after upgrade of kernel-default (from 5.6.0-rc7-1.g0801cd7-default) or util-linux (from 2.34-4.4) - SIGSTOPping udevd during losetup call allows the scan to succeed -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 Michal Koutný <mkoutny@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Assignee|kernel-maintainers@forge.pr |mkoutny@suse.com |ovo.novell.com | -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 http://bugzilla.suse.com/show_bug.cgi?id=1169932#c1 Michal Koutný <mkoutny@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |sbrabec@suse.com Assignee|mkoutny@suse.com |systemd-maintainers@suse.de --- Comment #1 from Michal Koutný <mkoutny@suse.com> --- The trigger are the two kernel patches that fixed "locking":
d3ef5536274f ("block: fix busy device checking in blk_drop_partitions") cb6b771b05c3 ("block: fix busy device checking in blk_drop_partitions again")
losetup isn't "atomic" operation:
strace -e ioctl losetup --find --show --partscan ~/image.0.raw (1) ioctl(3, LOOP_CTL_GET_FREE) = 1 ioctl(4, LOOP_SET_FD, 3) = 0 (2) ioctl(4, LOOP_SET_STATUS64, {lo_offset=0, lo_number=0, lo_flags=LO_FLAGS_PARTSCAN, lo_file_name="/home/mkoutny/image.0.raw", ...}) = 0
Somewhere between (1) and (2) uevent is triggered and udevd opens the device and (2) fails. Note that ioctl apparently succeeds (EBUSY is swallowed in kernel). TBH, I don't know what a good fix would be. Perhaps udevd being more careful when processing loop uevents? (I'm reassigning to systemd-maintainers, CCing util-linux maintainer). Also keyword: mkosi -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 Michal Koutný <mkoutny@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Blocks| |1170048 -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 http://bugzilla.suse.com/show_bug.cgi?id=1169932#c2 --- Comment #2 from Michal Koutný <mkoutny@suse.com> --- *** Bug 1170048 has been marked as a duplicate of this bug. *** -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 http://bugzilla.suse.com/show_bug.cgi?id=1169932#c4 --- Comment #4 from Michal Koutný <mkoutny@suse.com> --- (In reply to Michal Koutný from comment #1)
Also keyword: mkosi A workaround FWIW https://github.com/systemd/mkosi/compare/master...Werkov:workaround-losetup
-- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 http://bugzilla.suse.com/show_bug.cgi?id=1169932#c5 --- Comment #5 from Michal Koutný <mkoutny@suse.com> --- FTR. since this happens in RC kernel, I've looped in author of the changes [1] to get more information. [1] https://lore.kernel.org/lkml/20200423110738.GA102241@blackbook/ -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 http://bugzilla.suse.com/show_bug.cgi?id=1169932#c6 Michal Koutný <mkoutny@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |UPSTREAM --- Comment #6 from Michal Koutný <mkoutny@suse.com> --- This is being resolved in upstream [1], closing. [1] https://lore.kernel.org/linux-block/20200428085203.1852494-1-hch@lst.de/ -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 Jeffrey Cheung <jcheung@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jcheung@suse.com -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.suse.com/show_bug.cgi?id=1169932 Michal Koutný <mkoutny@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://bugzilla.suse.com/s | |how_bug.cgi?id=1170794 -- You are receiving this mail because: You are on the CC list for the bug.
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