On Sat, Sep 06, 2025 at 02:21:45PM +0200, Borislav Petkov wrote:
> From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>
>
> When
>
> 9770b428b1a2 ("crypto: ccp - Move dev_info/err messages for SEV/SNP init and shutdown")
>
> moved the error messages dumping so that they don't need to be issued by
> the callers, it missed the case where __sev_firmware_shutdown() calls
> __sev_platform_shutdown_locked() with a NULL argument which leads to
> a NULL ptr deref on the shutdown path, during suspend to disk:
>
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 0 P4D 0
> Oops: Oops: 0000 [#1] SMP NOPTI
> CPU: 0 UID: 0 PID: 983 Comm: hib.sh Not tainted 6.17.0-rc4+ #1 PREEMPT(voluntary)
> Hardware name: Supermicro Super Server/H12SSL-i, BIOS 2.5 09/08/2022
> RIP: 0010:__sev_platform_shutdown_locked.cold+0x0/0x21 [ccp]
>
> That rIP is:
>
> 00000000000006fd <__sev_platform_shutdown_locked.cold>:
> 6fd: 8b 13 mov (%rbx),%edx
> 6ff: 48 8b 7d 00 mov 0x0(%rbp),%rdi
> 703: 89 c1 mov %eax,%ecx
>
> Code: 74 05 31 ff 41 89 3f 49 8b 3e 89 ea 48 c7 c6 a0 8e 54 a0 41 bf 92 ff ff ff e8 e5 2e 09 e1 c6 05 2a d4 38 00 01 e9 26 af ff ff <8b> 13 48 8b 7d 00 89 c1 48 c7 c6 18 90 54 a0 89 44 24 04 e8 c1 2e
> RSP: 0018:ffffc90005467d00 EFLAGS: 00010282
> RAX: 00000000ffffff92 RBX: 0000000000000000 RCX: 0000000000000000
> ^^^^^^^^^^^^^^^^
> and %rbx is nice and clean.
>
> Call Trace:
> <TASK>
> __sev_firmware_shutdown.isra.0
> sev_dev_destroy
> psp_dev_destroy
> sp_destroy
> pci_device_shutdown
> device_shutdown
> kernel_power_off
> hibernate.cold
> state_store
> kernfs_fop_write_iter
> vfs_write
> ksys_write
> do_syscall_64
> entry_SYSCALL_64_after_hwframe
>
> Pass in a pointer to the function-local error var in the caller.
>
> With that addressed, suspending the ccp shows the error properly at
> least:
>
> ccp 0000:47:00.1: sev command 0x2 timed out, disabling PSP
> ccp 0000:47:00.1: SEV: failed to SHUTDOWN error 0x0, rc -110
> SEV-SNP: Leaking PFN range 0x146800-0x146a00
> SEV-SNP: PFN 0x146800 unassigned, dumping non-zero entries in 2M PFN region: [0x146800 - 0x146a00]
> ...
> ccp 0000:47:00.1: SEV-SNP firmware shutdown failed, rc -16, error 0x0
> ACPI: PM: Preparing to enter system sleep state S5
> kvm: exiting hardware virtualization
> reboot: Power down
>
> Btw, this driver is crying to be cleaned up to pass in a proper I/O
> struct which can be used to store information between the different
> functions, otherwise stuff like that will happen in the future again.
>
> Fixes: 9770b428b1a2 ("crypto: ccp - Move dev_info/err messages for SEV/SNP init and shutdown")
> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
> Cc: <stable@xxxxxxxxxx>
> ---
> drivers/crypto/ccp/sev-dev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
