[PATCH] nvme: Do not allocate 8kB buffer on stack

Pali Rohár
2021-12-09T10:07:16Z

Calling 'nvme scan' followed by 'nvme detail' crashes U-Boot on Turris
Omnia with the following error:

undefined instruction
pc : [<0a000000>] lr : [<7ff80bfc>]
reloc pc : [<8a8c0000>] lr : [<00840bfc>]
sp : 7fb2b908 ip : 0000002a fp : 02000000
r10: 04000000 r9 : 7fb2fed0 r8 : e1000000
r7 : 0c000000 r6 : 03000000 r5 : 06000000 r4 : 01000000
r3 : 7fb30928 r2 : 7fb30928 r1 : 00000000 r0 : 00000000
Flags: nZCv IRQs off FIQs off Mode SVC_32
Code: 0f0fb4f0 0f0fb4f0 0f0fb4f0 0f0fb4f0 (f0f04b0f)
Resetting CPU ...

This happens when nvme_print_info() tries to return to the caller. It
looks like this error is caused by trying to allocate 8 KiB of memory
on the stack by the two uses of ALLOC_CACHE_ALIGN_BUFFER().

Use malloc_cache_aligned() to allocate this memory dynamically instead.

This fixes 'nvme detail' on Turris Omnia.

Note that similar change was applied to file drivers/nvme/nvme.c in past by
commit 2f83481dff9c ("nvme: use page-aligned buffer for identify command").

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
drivers/nvme/nvme_show.c | 35 ++++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/nvme/nvme_show.c b/drivers/nvme/nvme_show.c
index 15e459da1acd..72cbac82bcca 100644
--- a/drivers/nvme/nvme_show.c
+++ b/drivers/nvme/nvme_show.c
@@ -106,24 +106,41 @@ int nvme_print_info(struct udevice *udev)
{
struct nvme_ns *ns = dev_get_priv(udev);
struct nvme_dev *dev = ns->dev;
- ALLOC_CACHE_ALIGN_BUFFER(char, buf_ns, sizeof(struct nvme_id_ns));
- struct nvme_id_ns *id = (struct nvme_id_ns *)buf_ns;
- ALLOC_CACHE_ALIGN_BUFFER(char, buf_ctrl, sizeof(struct nvme_id_ctrl));
- struct nvme_id_ctrl *ctrl = (struct nvme_id_ctrl *)buf_ctrl;
+ struct nvme_id_ctrl *ctrl;
+ struct nvme_id_ns *id;
+ int ret = 0;

- if (nvme_identify(dev, 0, 1, (dma_addr_t)(long)ctrl))
- return -EIO;
+ ctrl = memalign(dev->page_size, sizeof(struct nvme_id_ctrl));
+ if (!ctrl)
+ return -ENOMEM;
+
+ if (nvme_identify(dev, 0, 1, (dma_addr_t)(long)ctrl)) {
+ ret = -EIO;
+ goto free_ctrl;
+ }

print_optional_admin_cmd(le16_to_cpu(ctrl->oacs), ns->devnum);
print_optional_nvm_cmd(le16_to_cpu(ctrl->oncs), ns->devnum);
print_format_nvme_attributes(ctrl->fna, ns->devnum);

- if (nvme_identify(dev, ns->ns_id, 0, (dma_addr_t)(long)id))
- return -EIO;
+ id = memalign(dev->page_size, sizeof(struct nvme_id_ns));
+ if (!id) {
+ ret = -ENOMEM;
+ goto free_ctrl;
+ }
+
+ if (nvme_identify(dev, ns->ns_id, 0, (dma_addr_t)(long)id)) {
+ ret = -EIO;
+ goto free_id;
+ }

print_formats(id, ns);
print_data_protect_cap(id->dpc, ns->devnum);
print_metadata_cap(id->mc, ns->devnum);

- return 0;
+free_id:
+ free(id);
+free_ctrl:
+ free(ctrl);
+ return ret;
}
--
2.20.1