• Kees Cook's avatar
    pstore: Correctly initialize spinlock and flags · 78bfdaab
    Kees Cook authored
    commit 76d5692a upstream.
    
    The ram backend wasn't always initializing its spinlock correctly. Since
    it was coming from kzalloc memory, though, it was harmless on
    architectures that initialize unlocked spinlocks to 0 (at least x86 and
    ARM). This also fixes a possibly ignored flag setting too.
    
    When running under CONFIG_DEBUG_SPINLOCK, the following Oops was visible:
    
    [    0.760836] persistent_ram: found existing buffer, size 29988, start 29988
    [    0.765112] persistent_ram: found existing buffer, size 30105, start 30105
    [    0.769435] persistent_ram: found existing buffer, size 118542, start 118542
    [    0.785960] persistent_ram: found existing buffer, size 0, start 0
    [    0.786098] persistent_ram: found existing buffer, size 0, start 0
    [    0.786131] pstore: using zlib compression
    [    0.790716] BUG: spinlock bad magic on CPU#0, swapper/0/1
    [    0.790729]  lock: 0xffffffc0d1ca9bb0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
    [    0.790742] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc2+ #913
    [    0.790747] Hardware name: Google Kevin (DT)
    [    0.790750] Call trace:
    [    0.790768] [<ffffff900808ae88>] dump_backtrace+0x0/0x2bc
    [    0.790780] [<ffffff900808b164>] show_stack+0x20/0x28
    [    0.790794] [<ffffff9008460ee0>] dump_stack+0xa4/0xcc
    [    0.790809] [<ffffff9008113cfc>] spin_dump+0xe0/0xf0
    [    0.790821] [<ffffff9008113d3c>] spin_bug+0x30/0x3c
    [    0.790834] [<ffffff9008113e28>] do_raw_spin_lock+0x50/0x1b8
    [    0.790846] [<ffffff9008a2d2ec>] _raw_spin_lock_irqsave+0x54/0x6c
    [    0.790862] [<ffffff90083ac3b4>] buffer_size_add+0x48/0xcc
    [    0.790875] [<ffffff90083acb34>] persistent_ram_write+0x60/0x11c
    [    0.790888] [<ffffff90083aab1c>] ramoops_pstore_write_buf+0xd4/0x2a4
    [    0.790900] [<ffffff90083a9d3c>] pstore_console_write+0xf0/0x134
    [    0.790912] [<ffffff900811c304>] console_unlock+0x48c/0x5e8
    [    0.790923] [<ffffff900811da18>] register_console+0x3b0/0x4d4
    [    0.790935] [<ffffff90083aa7d0>] pstore_register+0x1a8/0x234
    [    0.790947] [<ffffff90083ac250>] ramoops_probe+0x6b8/0x7d4
    [    0.790961] [<ffffff90085ca548>] platform_drv_probe+0x7c/0xd0
    [    0.790972] [<ffffff90085c76ac>] driver_probe_device+0x1b4/0x3bc
    [    0.790982] [<ffffff90085c7ac8>] __device_attach_driver+0xc8/0xf4
    [    0.790996] [<ffffff90085c4bfc>] bus_for_each_drv+0xb4/0xe4
    [    0.791006] [<ffffff90085c7414>] __device_attach+0xd0/0x158
    [    0.791016] [<ffffff90085c7b18>] device_initial_probe+0x24/0x30
    [    0.791026] [<ffffff90085c648c>] bus_probe_device+0x50/0xe4
    [    0.791038] [<ffffff90085c35b8>] device_add+0x3a4/0x76c
    [    0.791051] [<ffffff90087d0e84>] of_device_add+0x74/0x84
    [    0.791062] [<ffffff90087d19b8>] of_platform_device_create_pdata+0xc0/0x100
    [    0.791073] [<ffffff90087d1a2c>] of_platform_device_create+0x34/0x40
    [    0.791086] [<ffffff900903c910>] of_platform_default_populate_init+0x58/0x78
    [    0.791097] [<ffffff90080831fc>] do_one_initcall+0x88/0x160
    [    0.791109] [<ffffff90090010ac>] kernel_init_freeable+0x264/0x31c
    [    0.791123] [<ffffff9008a25bd0>] kernel_init+0x18/0x11c
    [    0.791133] [<ffffff9008082ec0>] ret_from_fork+0x10/0x50
    [    0.793717] console [pstore-1] enabled
    [    0.797845] pstore: Registered ramoops as persistent store backend
    [    0.804647] ramoops: attached 0x100000@0xf7edc000, ecc: 0/0
    
    Fixes: 663deb47 ("pstore: Allow prz to control need for locking")
    Fixes: 10970449 ("pstore: Make spinlock per zone instead of global")
    Reported-by: default avatarBrian Norris <briannorris@chromium.org>
    Signed-off-by: default avatarKees Cook <keescook@chromium.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    78bfdaab
ram_core.c 13.4 KB