purex_item.iocb is defined as a 64-element u8 array, but 64 is the minimum size and it can be allocated larger. This makes it a standard empty flex array.
This was motivated by field-spanning write warnings during FPIN testing. https://lore.kernel.org/linux-nvme/20250709211919.49100-1-bgur...@redhat.com/ > kernel: memcpy: detected field-spanning write (size 60) of single field > "((uint8_t *)fpin_pkt + buffer_copy_offset)" > at drivers/scsi/qla2xxx/qla_isr.c:1221 (size 44) I removed the outer wrapper from the iocb flex array, so that it can be linked to `purex_item.size` with `__counted_by`. These changes remove the default minimum 64-byte allocation, requiring further changes. In `struct scsi_qla_host` the embedded `default_item` is now followed by `__default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE]` to reserve space that will be used as `default_item.iocb`. This is wrapped using the `TRAILING_OVERLAP()` macro helper, which effectively creates a union between flexible-array member `default_item.iocb` and `__default_item_iocb`. Since `struct pure_item` now contains a flexible-array member, the helper must be placed at the end of `struct scsi_qla_host` to prevent a `-Wflex-array-member-not-at-end` warning. `qla24xx_alloc_purex_item()` is adjusted to no longer expect the default minimum size to be part of `sizeof(struct purex_item)`, the entire flexible array size is added to the structure size for allocation. This also slightly changes the layout of the purex_item struct, as 2-bytes of padding are added between `size` and `iocb`. The resulting size is the same, but iocb is shifted 2-bytes (the original `purex_item` structure was padded at the end, after the 64-byte defined array size). I don't think this is a problem. Tested-by: Bryan Gurney <bgur...@redhat.com> Co-developed-by: Chris Leech <cle...@redhat.com> Signed-off-by: Chris Leech <cle...@redhat.com> Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org> --- drivers/scsi/qla2xxx/qla_def.h | 10 ++++++---- drivers/scsi/qla2xxx/qla_isr.c | 17 ++++++++--------- drivers/scsi/qla2xxx/qla_nvme.c | 2 +- drivers/scsi/qla2xxx/qla_os.c | 5 +++-- 4 files changed, 18 insertions(+), 16 deletions(-) diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h index cb95b7b12051..604e66bead1e 100644 --- a/drivers/scsi/qla2xxx/qla_def.h +++ b/drivers/scsi/qla2xxx/qla_def.h @@ -4890,9 +4890,7 @@ struct purex_item { struct purex_item *pkt); atomic_t in_use; uint16_t size; - struct { - uint8_t iocb[64]; - } iocb; + uint8_t iocb[] __counted_by(size); }; #include "qla_edif.h" @@ -5101,7 +5099,6 @@ typedef struct scsi_qla_host { struct list_head head; spinlock_t lock; } purex_list; - struct purex_item default_item; struct name_list_extended gnl; /* Count of active session/fcport */ @@ -5130,6 +5127,11 @@ typedef struct scsi_qla_host { #define DPORT_DIAG_IN_PROGRESS BIT_0 #define DPORT_DIAG_CHIP_RESET_IN_PROGRESS BIT_1 uint16_t dport_status; + + /* Must be last --ends in a flexible-array member. */ + TRAILING_OVERLAP(struct purex_item, default_item, iocb, + uint8_t __default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE]; + ); } scsi_qla_host_t; struct qla27xx_image_status { diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c index c4c6b5c6658c..4559b490614d 100644 --- a/drivers/scsi/qla2xxx/qla_isr.c +++ b/drivers/scsi/qla2xxx/qla_isr.c @@ -1077,17 +1077,17 @@ static struct purex_item * qla24xx_alloc_purex_item(scsi_qla_host_t *vha, uint16_t size) { struct purex_item *item = NULL; - uint8_t item_hdr_size = sizeof(*item); if (size > QLA_DEFAULT_PAYLOAD_SIZE) { - item = kzalloc(item_hdr_size + - (size - QLA_DEFAULT_PAYLOAD_SIZE), GFP_ATOMIC); + item = kzalloc(struct_size(item, iocb, size), GFP_ATOMIC); } else { if (atomic_inc_return(&vha->default_item.in_use) == 1) { item = &vha->default_item; goto initialize_purex_header; } else { - item = kzalloc(item_hdr_size, GFP_ATOMIC); + item = kzalloc( + struct_size(item, iocb, QLA_DEFAULT_PAYLOAD_SIZE), + GFP_ATOMIC); } } if (!item) { @@ -1127,17 +1127,16 @@ qla24xx_queue_purex_item(scsi_qla_host_t *vha, struct purex_item *pkt, * @vha: SCSI driver HA context * @pkt: ELS packet */ -static struct purex_item -*qla24xx_copy_std_pkt(struct scsi_qla_host *vha, void *pkt) +static struct purex_item * +qla24xx_copy_std_pkt(struct scsi_qla_host *vha, void *pkt) { struct purex_item *item; - item = qla24xx_alloc_purex_item(vha, - QLA_DEFAULT_PAYLOAD_SIZE); + item = qla24xx_alloc_purex_item(vha, QLA_DEFAULT_PAYLOAD_SIZE); if (!item) return item; - memcpy(&item->iocb, pkt, sizeof(item->iocb)); + memcpy(&item->iocb, pkt, QLA_DEFAULT_PAYLOAD_SIZE); return item; } diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c index 8ee2e337c9e1..92488890bc04 100644 --- a/drivers/scsi/qla2xxx/qla_nvme.c +++ b/drivers/scsi/qla2xxx/qla_nvme.c @@ -1308,7 +1308,7 @@ void qla2xxx_process_purls_iocb(void **pkt, struct rsp_que **rsp) ql_dbg(ql_dbg_unsol, vha, 0x2121, "PURLS OP[%01x] size %d xchg addr 0x%x portid %06x\n", - item->iocb.iocb[3], item->size, uctx->exchange_address, + item->iocb[3], item->size, uctx->exchange_address, fcport->d_id.b24); /* +48 0 1 2 3 4 5 6 7 8 9 A B C D E F * ----- ----------------------------------------------- diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c index d4b484c0fd9d..253f802605d6 100644 --- a/drivers/scsi/qla2xxx/qla_os.c +++ b/drivers/scsi/qla2xxx/qla_os.c @@ -6459,9 +6459,10 @@ void qla24xx_process_purex_rdp(struct scsi_qla_host *vha, void qla24xx_free_purex_item(struct purex_item *item) { - if (item == &item->vha->default_item) + if (item == &item->vha->default_item) { memset(&item->vha->default_item, 0, sizeof(struct purex_item)); - else + memset(&item->vha->__default_item_iocb, 0, QLA_DEFAULT_PAYLOAD_SIZE); + } else kfree(item); } -- 2.43.0
