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EDAC/ghes: Clear scanned data on unload
Commit b972fdb ("EDAC/ghes: Fix NULL pointer dereference in ghes_edac_register()") didn't clear all the information from the scanned system and, more specifically, left ghes_hw.num_dimms to its previous value. On a second load (CONFIG_DEBUG_TEST_DRIVER_REMOVE=y), the driver would use the leftover num_dimms value which is not 0 and thus the 0 check in enumerate_dimms() will get bypassed and it would go directly to the pointer deref: d = &hw->dimms[hw->num_dimms]; which is, of course, NULL: #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc4+ #7 Hardware name: GIGABYTE MZ01-CE1-00/MZ01-CE1-00, BIOS F02 08/29/2018 RIP: 0010:enumerate_dimms.cold+0x7b/0x375 Reset the whole ghes_hw on driver unregister so that no stale values are used on a second system scan. Fixes: b972fdb ("EDAC/ghes: Fix NULL pointer dereference in ghes_edac_register()") Cc: Shiju Jose <shiju.jose@huawei.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200911164817.GA19320@zn.tnic
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