diff options
| author | Bodo Stroesser | 2020-06-29 11:37:56 +0200 |
|---|---|---|
| committer | Martin K. Petersen | 2020-06-29 21:44:57 -0400 |
| commit | 5a0c256d96f020e4771f6fd5524b80f89a2d3132 (patch) | |
| tree | 084dca3414068ad8d4794286eb5e21d3113bb983 | |
| parent | b7a80dac0f1f16ca5714b89ace8a3fc079686875 (diff) | |
scsi: target: tcmu: Fix crash on ARM during cmd completion
If tcmu_handle_completions() has to process a padding shorter than
sizeof(struct tcmu_cmd_entry), the current call to
tcmu_flush_dcache_range() with sizeof(struct tcmu_cmd_entry) as length
param is wrong and causes crashes on e.g. ARM, because
tcmu_flush_dcache_range() in this case calls
flush_dcache_page(vmalloc_to_page(start)); with start being an invalid
address above the end of the vmalloc'ed area.
The fix is to use the minimum of remaining ring space and sizeof(struct
tcmu_cmd_entry) as the length param.
The patch was tested on kernel 4.19.118.
See https://bugzilla.kernel.org/show_bug.cgi?id=208045#c10
Link: https://lore.kernel.org/r/20200629093756.8947-1-bstroesser@ts.fujitsu.com
Tested-by: JiangYu <lnsyyj@hotmail.com>
Acked-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/target/target_core_user.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 3885ca532f8f..366878b0b2fd 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1221,7 +1221,14 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned; - tcmu_flush_dcache_range(entry, sizeof(*entry)); + /* + * Flush max. up to end of cmd ring since current entry might + * be a padding that is shorter than sizeof(*entry) + */ + size_t ring_left = head_to_end(udev->cmdr_last_cleaned, + udev->cmdr_size); + tcmu_flush_dcache_range(entry, ring_left < sizeof(*entry) ? + ring_left : sizeof(*entry)); if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) { UPDATE_HEAD(udev->cmdr_last_cleaned, |