On Fri, Feb 14, 2014 at 08:23:54PM +0200, Imre Deak wrote: > pci_get_class(class, from) drops the refcount for 'from', so the > extra pci_dev_put we do on it will result in a use after free bug > starting with the WARN below. > > Regression introduced in > > commit 6a9c4b35e6696a63805b6da5e4889c6986e9ee1b > Author: Rui Guo <firemeteor@xxxxxxxxxxxxxxxxxxxxx> > Date: Wed Jun 19 21:10:23 2013 +0800 > > drm/i915: Fix PCH detect with multiple ISA bridges in VM > > [ 164.338460] WARNING: CPU: 1 PID: 2094 at include/linux/kref.h:47 klist_next+0xae/0x110() > [ 164.347731] CPU: 1 PID: 2094 Comm: modprobe Tainted: G O 3.13.0-imre+ #354 > [ 164.356468] Hardware name: Intel Corp. VALLEYVIEW B0 PLATFORM/NOTEBOOK, BIOS BYTICRB1.X64.0062.R70.1310112051 10/11/2013 > [ 164.368796] Call Trace: > [ 164.371609] [<ffffffff816a32a6>] dump_stack+0x4e/0x7a > [ 164.377447] [<ffffffff8104f75d>] warn_slowpath_common+0x7d/0xa0 > [ 164.384238] [<ffffffff8104f83a>] warn_slowpath_null+0x1a/0x20 > [ 164.390851] [<ffffffff8169aeae>] klist_next+0xae/0x110 > [ 164.396777] [<ffffffff8130a110>] ? pci_do_find_bus+0x70/0x70 > [ 164.403286] [<ffffffff813cb4a9>] bus_find_device+0x89/0xc0 > [ 164.409719] [<ffffffff8130a373>] pci_get_dev_by_id+0x63/0xa0 > [ 164.416238] [<ffffffff8130a4e4>] pci_get_class+0x44/0x50 > [ 164.422433] [<ffffffffa034821f>] intel_dsm_detect+0x16f/0x1f0 [i915] > [ 164.429801] [<ffffffffa03482ae>] intel_register_dsm_handler+0xe/0x10 [i915] > [ 164.437831] [<ffffffffa02d30fe>] i915_driver_load+0xafe/0xf30 [i915] > [ 164.445126] [<ffffffff8158a150>] ? intel_alloc_coherent+0x110/0x110 > [ 164.452340] [<ffffffffa0148c07>] drm_dev_register+0xc7/0x150 [drm] > [ 164.459462] [<ffffffffa014b23f>] drm_get_pci_dev+0x11f/0x1f0 [drm] > [ 164.466554] [<ffffffff816abb81>] ? _raw_spin_unlock_irqrestore+0x51/0x70 > [ 164.474287] [<ffffffffa02cf7a6>] i915_pci_probe+0x56/0x60 [i915] > [ 164.481185] [<ffffffff8130a028>] pci_device_probe+0x78/0xf0 > [ 164.487603] [<ffffffff813cd495>] driver_probe_device+0x155/0x350 > [ 164.494505] [<ffffffff813cd74e>] __driver_attach+0x6e/0xa0 > [ 164.500826] [<ffffffff813cd6e0>] ? __device_attach+0x50/0x50 > [ 164.507333] [<ffffffff813cb2be>] bus_for_each_dev+0x6e/0xc0 > [ 164.513752] [<ffffffff813ccefe>] driver_attach+0x1e/0x20 > [ 164.519870] [<ffffffff813cc958>] bus_add_driver+0x138/0x260 > [ 164.526289] [<ffffffffa0188000>] ? 0xffffffffa0187fff > [ 164.532116] [<ffffffff813cde78>] driver_register+0x98/0xe0 > [ 164.538558] [<ffffffffa0188000>] ? 0xffffffffa0187fff > [ 164.544389] [<ffffffff813087b0>] __pci_register_driver+0x60/0x70 > [ 164.551336] [<ffffffffa014b37d>] drm_pci_init+0x6d/0x120 [drm] > [ 164.558040] [<ffffffffa0188000>] ? 0xffffffffa0187fff > [ 164.563928] [<ffffffffa018806a>] i915_init+0x6a/0x6c [i915] > [ 164.570363] [<ffffffff810002da>] do_one_initcall+0xaa/0x160 > [ 164.576783] [<ffffffff8103b140>] ? set_memory_nx+0x40/0x50 > [ 164.583100] [<ffffffff810ce7f5>] load_module+0x1fb5/0x2550 > [ 164.589410] [<ffffffff810caab0>] ? store_uevent+0x40/0x40 > [ 164.595628] [<ffffffff810cee7d>] SyS_init_module+0xed/0x100 > [ 164.602048] [<ffffffff816b3c52>] system_call_fastpath+0x16/0x1b > > v2: simplify the loop further (Chris) > > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> Reported-by: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65652 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74161 Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
