David, Al,
commit 23bf1b6be9c2 ("kernfs, sysfs, cgroup, intel_rdt: Support fs_context")
seems to have introduced a bug; at least that's the commit I bisected the
following oops down to:
[ 0.827317] BUG: unable to handle kernel NULL pointer dereference at 0000000000000220
[ 0.829771] #PF error: [normal kernel read fault]
[ 0.831141] PGD 800000007f927067 P4D 800000007f927067 PUD 7f928067 PMD 0
[ 0.833116] Oops: 0000 [#1] PREEMPT SMP PTI
[ 0.834330] CPU: 1 PID: 46 Comm: mount Tainted: G T 5.0.0-rc2+ #38
[ 0.836478] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
[ 0.839322] RIP: 0010:sysfs_init_fs_context+0x82/0xd0
[ 0.840777] Code: 15 fb ef af 01 48 89 45 08 48 c7 45 10 72 65 65 62 48 c7 03 60 66 22 8f 48 85 ff 48 89 55 00 74 09 f0 ff 8f 5
[ 0.846170] RSP: 0018:ffffa55e8041bdb8 EFLAGS: 00010202
[ 0.847693] RAX: 0000000000000000 RBX: ffff949bbc0fee00 RCX: 0000000000000000
[ 0.850013] RDX: ffff949bbc878d00 RSI: 0000000000000000 RDI: ffffffff8f645c40
[ 0.852134] RBP: ffff949bbc0ff400 R08: 0000000000000001 R09: 00000000001ef140
[ 0.854211] R10: 0000000136a1068e R11: 0000000000000001 R12: 0000000000000000
[ 0.856225] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000008000
[ 0.858350] FS: 000000000050b558(0000) GS:ffff949bbce00000(0000) knlGS:0000000000000000
[ 0.860738] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.862391] CR2: 0000000000000220 CR3: 000000007c1f0004 CR4: 00000000003606e0
[ 0.864463] Call Trace:
[ 0.865200] alloc_fs_context+0xfa/0x170
[ 0.866349] do_mount+0x8fa/0xf50
[ 0.867310] ? memdup_user+0x4b/0x70
[ 0.868350] ksys_mount+0xba/0xd0
[ 0.869291] __x64_sys_mount+0x21/0x30
[ 0.870390] do_syscall_64+0x6a/0x3f4
[ 0.871465] ? lockdep_hardirqs_off+0x79/0xd0
[ 0.872744] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 0.874106] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 0.875584] RIP: 0033:0x4bf02f
[ 0.876496] Code: e8 06 21 f4 ff 5a c3 48 63 ff 50 48 63 d2 b8 67 00 00 00 0f 05 48 89 c7 e8 ee 20 f4 ff 5a c3 49 89 ca 50 b8 8
[ 0.882329] RSP: 002b:00007ffc1befbd80 EFLAGS: 00000212 ORIG_RAX: 00000000000000a5
[ 0.884110] RAX: ffffffffffffffda RBX: 00007ffc1befc058 RCX: 00000000004bf02f
[ 0.885871] RDX: 00007ffc1befdf84 RSI: 00007ffc1befdf90 RDI: 00007ffc1befdf8a
[ 0.888102] RBP: 00007ffc1befdf8a R08: 0000000000000000 R09: 8080808080808080
[ 0.890154] R10: 0000000000008000 R11: 0000000000000212 R12: 00007ffc1befdf90
[ 0.892107] R13: 00007ffc1befdf84 R14: 0000000000008000 R15: 0000000000000000
[ 0.893537] CR2: 0000000000000220
[ 0.894467] ---[ end trace 0a9affd2a96301a9 ]---
[ 0.896230] RIP: 0010:sysfs_init_fs_context+0x82/0xd0
[ 0.897494] Code: 15 fb ef af 01 48 89 45 08 48 c7 45 10 72 65 65 62 48 c7 03 60 66 22 8f 48 85 ff 48 89 55 00 74 09 f0 ff 8f 5
[ 0.903017] RSP: 0018:ffffa55e8041bdb8 EFLAGS: 00010202
[ 0.904315] RAX: 0000000000000000 RBX: ffff949bbc0fee00 RCX: 0000000000000000
[ 0.905857] RDX: ffff949bbc878d00 RSI: 0000000000000000 RDI: ffffffff8f645c40
[ 0.907444] RBP: ffff949bbc0ff400 R08: 0000000000000001 R09: 00000000001ef140
[ 0.909973] R10: 0000000136a1068e R11: 0000000000000001 R12: 0000000000000000
[ 0.911415] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000008000
[ 0.913726] FS: 000000000050b558(0000) GS:ffff949bbce00000(0000) knlGS:0000000000000000
[ 0.916710] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.918129] CR2: 0000000000000220 CR3: 000000007c1f0004 CR4: 00000000003606e0
This occurs while trying to mount sysfs in initramfs
mount -n -t sysfs sysfs /sys
All this obviously runs in qemu; config and further information are available upon request.
Thanks,
Dominik
