• Rusty Russell's avatar
    module: don't unlink the module until we've removed all exposure. · 944a1fa0
    Rusty Russell authored
    Otherwise we get a race between unload and reload of the same module:
    the new module doesn't see the old one in the list, but then fails because
    it can't register over the still-extant entries in sysfs:
    
     [  103.981925] ------------[ cut here ]------------
     [  103.986902] WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0xab/0xd0()
     [  103.993606] Hardware name: CrownBay Platform
     [  103.998075] sysfs: cannot create duplicate filename '/module/pch_gbe'
     [  104.004784] Modules linked in: pch_gbe(+) [last unloaded: pch_gbe]
     [  104.011362] Pid: 3021, comm: modprobe Tainted: G        W    3.9.0-rc5+ #5
     [  104.018662] Call Trace:
     [  104.021286]  [<c103599d>] warn_slowpath_common+0x6d/0xa0
     [  104.026933]  [<c1168c8b>] ? sysfs_add_one+0xab/0xd0
     [  104.031986]  [<c1168c8b>] ? sysfs_add_one+0xab/0xd0
     [  104.037000]  [<c1035a4e>] warn_slowpath_fmt+0x2e/0x30
     [  104.042188]  [<c1168c8b>] sysfs_add_one+0xab/0xd0
     [  104.046982]  [<c1168dbe>] create_dir+0x5e/0xa0
     [  104.051633]  [<c1168e78>] sysfs_create_dir+0x78/0xd0
     [  104.056774]  [<c1262bc3>] kobject_add_internal+0x83/0x1f0
     [  104.062351]  [<c126daf6>] ? kvasprintf+0x46/0x60
     [  104.067231]  [<c1262ebd>] kobject_add_varg+0x2d/0x50
     [  104.072450]  [<c1262f07>] kobject_init_and_add+0x27/0x30
     [  104.078075]  [<c1089240>] mod_sysfs_setup+0x80/0x540
     [  104.083207]  [<c1260851>] ? module_bug_finalize+0x51/0xc0
     [  104.088720]  [<c108ab29>] load_module+0x1429/0x18b0
    
    We can teardown sysfs first, then to be sure, put the state in
    MODULE_STATE_UNFORMED so it's ignored while we deconstruct it.
    Reported-by: default avatarVeaceslav Falico <vfalico@redhat.com>
    Tested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
    Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
    944a1fa0
module.c 96.9 KB