4.16-stable review patch. If anyone has any objections, please let me know.
------------------ From: Brijesh Singh <[email protected]> commit 716c7c32eae4b8a45c4f5602b50453865929b670 upstream. Paulian reported the below kernel crash on Ryzen 5 system: BUG: unable to handle kernel NULL pointer dereference at 0000000000000073 RIP: 0010:.LC0+0x41f/0xa00 RSP: 0018:ffffa9968003bdd0 EFLAGS: 00010002 RAX: ffffffffb113b130 RBX: 0000000000000000 RCX: 00000000000005a7 RDX: 00000000000000ff RSI: ffff8b46dee651a0 RDI: ffffffffb1bd617c RBP: 0000000000000246 R08: 00000000000251a0 R09: 0000000000000000 R10: ffffd81f11a38200 R11: ffff8b52e8e0a161 R12: ffffffffb19db220 R13: 0000000000000007 R14: ffffffffb17e4888 R15: 5dccd7affc30a31e FS: 0000000000000000(0000) GS:ffff8b46dee40000(0000) knlGS:0000000000000000 CR2: 0000000000000073 CR3: 000080128120a000 CR4: 00000000003406e0 Call Trace: ? sp_get_psp_master_device+0x56/0x80 ? map_properties+0x540/0x540 ? psp_pci_init+0x20/0xe0 ? map_properties+0x540/0x540 ? sp_mod_init+0x16/0x1a ? do_one_initcall+0x4b/0x190 ? kernel_init_freeable+0x19b/0x23c ? rest_init+0xb0/0xb0 ? kernel_init+0xa/0x100 ? ret_from_fork+0x22/0x40 Since Ryzen does not support PSP/SEV firmware hence i->psp_data will NULL in all sp instances. In those cases, 'i' will point to the list head after list_for_each_entry(). Dereferencing the head will cause kernel crash. Add check to call get master device only when PSP/SEV is detected. Reported-by: Paulian Bogdan Marinca <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Tom Lendacky <[email protected]> CC: Gary R Hook <[email protected]> Cc: [email protected] Signed-off-by: Brijesh Singh <[email protected]> Signed-off-by: Herbert Xu <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/crypto/ccp/sp-dev.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/crypto/ccp/sp-dev.c +++ b/drivers/crypto/ccp/sp-dev.c @@ -252,12 +252,12 @@ struct sp_device *sp_get_psp_master_devi goto unlock; list_for_each_entry(i, &sp_units, entry) { - if (i->psp_data) + if (i->psp_data && i->get_psp_master_device) { + ret = i->get_psp_master_device(); break; + } } - if (i->get_psp_master_device) - ret = i->get_psp_master_device(); unlock: write_unlock_irqrestore(&sp_unit_lock, flags); return ret;
