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| author | Bodo Stroesser <bstroesser@ts.fujitsu.com> | 2020-06-29 12:37:56 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-03 12:24:19 +0300 |
| commit | b5cd5c1e708721c421e6a101a949d462a8d840f4 (patch) | |
| tree | 52012caebd183beac2a72a0eedac7aa979a6051d /drivers/target | |
| parent | f4e860765108133941c9c964af336769b487c388 (diff) | |
| download | linux-b5cd5c1e708721c421e6a101a949d462a8d840f4.tar.xz | |
scsi: target: tcmu: Fix crash on ARM during cmd completion
[ Upstream commit 5a0c256d96f020e4771f6fd5524b80f89a2d3132 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/target')
| -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 9c05e820857a..91dbac7446a4 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1231,7 +1231,14 @@ 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, |