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authorBorislav Petkov <bp@suse.de>2020-09-11 18:17:30 +0200
committerBorislav Petkov <bp@suse.de>2020-09-15 09:42:15 +0200
commit251c54ea26fa6029b01a76161a37a12fde5124e4 (patch)
tree69b3871bd424b8f32b0f50a7b579231607396408 /drivers/edac/ghes_edac.c
parentcd8100f1f3be406a4e0e122e7307ac0fca6d57cc (diff)
EDAC/ghes: Check whether the driver is on the safe list correctly
With CONFIG_DEBUG_TEST_DRIVER_REMOVE=y, a system would try to probe, unregister and probe again a driver. When ghes_edac is attempted to be loaded on a system which is not on the safe platforms list, ghes_edac_register() would return early. The unregister counterpart ghes_edac_unregister() would still attempt to unregister and exit early at the refcount test, leading to the refcount underflow below. In order to not do *anything* on the unregister path too, reuse the force_load parameter and check it on that path too, before fumbling with the refcount. ghes_edac: ghes_edac_register: entry ghes_edac: ghes_edac_register: return -ENODEV ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 10 PID: 1 at lib/refcount.c:28 refcount_warn_saturate+0xb9/0x100 Modules linked in: CPU: 10 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc4+ #12 Hardware name: GIGABYTE MZ01-CE1-00/MZ01-CE1-00, BIOS F02 08/29/2018 RIP: 0010:refcount_warn_saturate+0xb9/0x100 Code: 82 e8 fb 8f 4d 00 90 0f 0b 90 90 c3 80 3d 55 4c f5 00 00 75 88 c6 05 4c 4c f5 00 01 90 48 c7 c7 d0 8a 10 82 e8 d8 8f 4d 00 90 <0f> 0b 90 90 c3 80 3d 30 4c f5 00 00 0f 85 61 ff ff ff c6 05 23 4c RSP: 0018:ffffc90000037d58 EFLAGS: 00010292 RAX: 0000000000000026 RBX: ffff88840b8da000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff8216b24f RDI: 00000000ffffffff RBP: ffff88840c662e00 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000046 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88840ee80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000800002211000 CR4: 00000000003506e0 Call Trace: ghes_edac_unregister ghes_remove platform_drv_remove really_probe driver_probe_device device_driver_attach __driver_attach ? device_driver_attach ? device_driver_attach bus_for_each_dev bus_add_driver driver_register ? bert_init ghes_init do_one_initcall ? rcu_read_lock_sched_held kernel_init_freeable ? rest_init kernel_init ret_from_fork ... ghes_edac: ghes_edac_unregister: FALSE, refcount: -1073741824 Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200911164950.GB19320@zn.tnic
Diffstat (limited to 'drivers/edac/ghes_edac.c')
-rw-r--r--drivers/edac/ghes_edac.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index bf7fb9f3e117..94d1e3165052 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -508,6 +508,7 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
if (!force_load && idx < 0)
return -ENODEV;
} else {
+ force_load = true;
idx = 0;
}
@@ -629,6 +630,9 @@ void ghes_edac_unregister(struct ghes *ghes)
struct mem_ctl_info *mci;
unsigned long flags;
+ if (!force_load)
+ return;
+
mutex_lock(&ghes_reg_mutex);
system_scanned = false;