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Bug #5562

ZFS sa_handle's violate kmem invariants, debug kernels panic on boot

Added by Rich Lowe over 5 years ago. Updated over 5 years ago.

Status:
Closed
Priority:
Urgent
Assignee:
-
Category:
zfs - Zettabyte File System
Start date:
2015-01-26
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:
needs-triage
Gerrit CR:

Description

debug kernels panic with the message:

assertion failed: dbu->dbu_evict_func == NULL

The stack is:

fffffffffbc7fca0 zfs`sa_handle_get_from_db+0x143(ffffff00a63ff540,
ffffff00a65f7c68, ffffff00a6655e90, 0, ffffff00a6655f78)
fffffffffbc7fd20 zfs`zfs_znode_sa_init+0x179(ffffff00a5b95000, ffffff00a6655e90
, ffffff00a65f7c68, 2c, 0)
fffffffffbc7ff20 zfs`zfs_znode_alloc+0xdc(ffffff00a5b95000, ffffff00a65f7c68,
800, 2c, 0)
fffffffffbc7ffd0 zfs`zfs_zget+0x101(ffffff00a5b95000, 4, fffffffffbc7ffe8)
fffffffffbc80020 zfs`zfs_mountroot+0x163(fffffffffbff3da0, 0)
fffffffffbc80040 fsop_mountroot+0x17(fffffffffbff3da0, 0)
fffffffffbc80070 rootconf+0x12d()
fffffffffbc800b0 vfs_mountroot+0x6f()
fffffffffbc800f0 main+0x198()
fffffffffbc80100 _locore_start+0x90()

(the assert is via the inlined and thus invisible (which really gets my goat, fwiw) dmu_buf_init_user)

This code violates the invariant spelled out in kmem_cache_create(9F) that upon freeing an object with kmem_cache_free() it must be "in its constructed state", thus the handle we get from kmem_cache_alloc in the NULL case of sa_handle_get_from_db() might not be in its constructed state, and thus will fail the NULL assertion.

In my case, this causes us to panic when mounting /.

History

#1

Updated by Justin Gibbs over 5 years ago

#2

Updated by Electric Monk over 5 years ago

  • Status changed from New to Closed
  • % Done changed from 0 to 100

git commit 0fda3cc5c1c5a1d9bdea6d52637bef6e781549c9

commit  0fda3cc5c1c5a1d9bdea6d52637bef6e781549c9
Author: Justin T. Gibbs <justing@spectralogic.com>
Date:   2015-01-27T16:13:19.000Z

    5562 ZFS sa_handle's violate kmem invariants, debug kernels panic on boot
    Reviewed by: Matthew Ahrens <mahrens@delphix.com>
    Reviewed by: Robert Mustacchi <rm@fingolfin.org>
    Reviewed by: George Wilson <george@delphix.com>
    Reviewed by: Rich Lowe <richlowe@richlowe.net>
    Approved by: Dan McDonald <danmcd@omniti.com>

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