On 6/27/24 03:00, Niklas Cassel wrote:
> If the ata_port_alloc() call in ata_host_alloc() fails,
> ata_host_release() will get called.
>
> However, the code in ata_host_release() tries to free ata_port struct
> members unconditionally, which can lead to the following:
>
> BUG: unable to handle page fault for address: 0000000000003990
> PGD 0 P4D 0
> Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 10 PID: 594 Comm: (udev-worker) Not tainted 6.10.0-rc5 #44
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
> RIP: 0010:ata_host_release.cold+0x2f/0x6e [libata]
> Code: e4 4d 63 f4 44 89 e2 48 c7 c6 90 ad 32 c0 48 c7 c7 d0 70 33 c0 49 83 c6 0e 41
> RSP: 0018:ffffc90000ebb968 EFLAGS: 00010246
> RAX: 0000000000000041 RBX: ffff88810fb52e78 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffff88813b3218c0 RDI: ffff88813b3218c0
> RBP: ffff88810fb52e40 R08: 0000000000000000 R09: 6c65725f74736f68
> R10: ffffc90000ebb738 R11: 73692033203a746e R12: 0000000000000004
> R13: 0000000000000000 R14: 0000000000000011 R15: 0000000000000006
> FS: 00007f6cc55b9980(0000) GS:ffff88813b300000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000003990 CR3: 00000001122a2000 CR4: 0000000000750ef0
> PKRU: 55555554
> Call Trace:
> <TASK>
> ? __die_body.cold+0x19/0x27
> ? page_fault_oops+0x15a/0x2f0
> ? exc_page_fault+0x7e/0x180
> ? asm_exc_page_fault+0x26/0x30
> ? ata_host_release.cold+0x2f/0x6e [libata]
> ? ata_host_release.cold+0x2f/0x6e [libata]
> release_nodes+0x35/0xb0
> devres_release_group+0x113/0x140
> ata_host_alloc+0xed/0x120 [libata]
> ata_host_alloc_pinfo+0x14/0xa0 [libata]
> ahci_init_one+0x6c9/0xd20 [ahci]
>
> Do not access ata_port struct members unconditionally.
>
> Fixes: 633273a3ed1c ("libata-pmp: hook PMP support and enable it")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx>
Looks good, with a nit below. This should be queued as soon as possible as a
6.10 fix patch.
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
> drivers/ata/libata-core.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index e1bf8a19b3c8..88e32f638f33 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -5518,10 +5518,12 @@ static void ata_host_release(struct kref *kref)
> for (i = 0; i < host->n_ports; i++) {
> struct ata_port *ap = host->ports[i];
>
> - kfree(ap->pmp_link);
> - kfree(ap->slave_link);
> - kfree(ap->ncq_sense_buf);
> - kfree(ap);
> + if (ap) {
> + kfree(ap->pmp_link);
> + kfree(ap->slave_link);
> + kfree(ap->ncq_sense_buf);
> + kfree(ap);
> + }
> host->ports[i] = NULL;
Nit: this line can go inside the if as well. Or even better: reverse the if
condition and continue to ignore NULL ports.
for (i = 0; i < host->n_ports; i++) {
struct ata_port *ap = host->ports[i];
if (!ap)
continue;
kfree(ap->pmp_link);
kfree(ap->slave_link);
kfree(ap->ncq_sense_buf);
kfree(ap);
host->ports[i] = NULL;
}
--
Damien Le Moal
Western Digital Research
