The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 4b5142905d4ff58a4b93f7c8eaa7ba829c0a53c9 Mon Sep 17 00:00:00 2001
From: Nikos Tsironis <ntsironis(a)arrikto.com>
Date: Fri, 27 Mar 2020 16:01:08 +0200
Subject: [PATCH] dm clone: Fix handling of partial region discards
There is a bug in the way dm-clone handles discards, which can lead to
discarding the wrong blocks or trying to discard blocks beyond the end
of the device.
This could lead to data corruption, if the destination device indeed
discards the underlying blocks, i.e., if the discard operation results
in the original contents of a block to be lost.
The root of the problem is the code that calculates the range of regions
covered by a discard request and decides which regions to discard.
Since dm-clone handles the device in units of regions, we don't discard
parts of a region, only whole regions.
The range is calculated as:
rs = dm_sector_div_up(bio->bi_iter.bi_sector, clone->region_size);
re = bio_end_sector(bio) >> clone->region_shift;
, where 'rs' is the first region to discard and (re - rs) is the number
of regions to discard.
The bug manifests when we try to discard part of a single region, i.e.,
when we try to discard a block with size < region_size, and the discard
request both starts at an offset with respect to the beginning of that
region and ends before the end of the region.
The root cause is the following comparison:
if (rs == re)
// skip discard and complete original bio immediately
, which doesn't take into account that 'rs' might be greater than 're'.
Thus, we then issue a discard request for the wrong blocks, instead of
skipping the discard all together.
Fix the check to also take into account the above case, so we don't end
up discarding the wrong blocks.
Also, add some range checks to dm_clone_set_region_hydrated() and
dm_clone_cond_set_range(), which update dm-clone's region bitmap.
Note that the aforementioned bug doesn't cause invalid memory accesses,
because dm_clone_is_range_hydrated() returns True for this case, so the
checks are just precautionary.
Fixes: 7431b7835f55 ("dm: add clone target")
Cc: stable(a)vger.kernel.org # v5.4+
Signed-off-by: Nikos Tsironis <ntsironis(a)arrikto.com>
Signed-off-by: Mike Snitzer <snitzer(a)redhat.com>
diff --git a/drivers/md/dm-clone-metadata.c b/drivers/md/dm-clone-metadata.c
index c05b12110456..199e7af00858 100644
--- a/drivers/md/dm-clone-metadata.c
+++ b/drivers/md/dm-clone-metadata.c
@@ -850,6 +850,12 @@ int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long re
struct dirty_map *dmap;
unsigned long word, flags;
+ if (unlikely(region_nr >= cmd->nr_regions)) {
+ DMERR("Region %lu out of range (total number of regions %lu)",
+ region_nr, cmd->nr_regions);
+ return -ERANGE;
+ }
+
word = region_nr / BITS_PER_LONG;
spin_lock_irqsave(&cmd->bitmap_lock, flags);
@@ -879,6 +885,13 @@ int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start,
struct dirty_map *dmap;
unsigned long word, region_nr;
+ if (unlikely(start >= cmd->nr_regions || (start + nr_regions) < start ||
+ (start + nr_regions) > cmd->nr_regions)) {
+ DMERR("Invalid region range: start %lu, nr_regions %lu (total number of regions %lu)",
+ start, nr_regions, cmd->nr_regions);
+ return -ERANGE;
+ }
+
spin_lock_irq(&cmd->bitmap_lock);
if (cmd->read_only) {
diff --git a/drivers/md/dm-clone-target.c b/drivers/md/dm-clone-target.c
index d1e1b5b56b1b..022dddcad647 100644
--- a/drivers/md/dm-clone-target.c
+++ b/drivers/md/dm-clone-target.c
@@ -293,10 +293,17 @@ static inline unsigned long bio_to_region(struct clone *clone, struct bio *bio)
/* Get the region range covered by the bio */
static void bio_region_range(struct clone *clone, struct bio *bio,
- unsigned long *rs, unsigned long *re)
+ unsigned long *rs, unsigned long *nr_regions)
{
+ unsigned long end;
+
*rs = dm_sector_div_up(bio->bi_iter.bi_sector, clone->region_size);
- *re = bio_end_sector(bio) >> clone->region_shift;
+ end = bio_end_sector(bio) >> clone->region_shift;
+
+ if (*rs >= end)
+ *nr_regions = 0;
+ else
+ *nr_regions = end - *rs;
}
/* Check whether a bio overwrites a region */
@@ -454,7 +461,7 @@ static void trim_bio(struct bio *bio, sector_t sector, unsigned int len)
static void complete_discard_bio(struct clone *clone, struct bio *bio, bool success)
{
- unsigned long rs, re;
+ unsigned long rs, nr_regions;
/*
* If the destination device supports discards, remap and trim the
@@ -463,9 +470,9 @@ static void complete_discard_bio(struct clone *clone, struct bio *bio, bool succ
*/
if (test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags) && success) {
remap_to_dest(clone, bio);
- bio_region_range(clone, bio, &rs, &re);
+ bio_region_range(clone, bio, &rs, &nr_regions);
trim_bio(bio, rs << clone->region_shift,
- (re - rs) << clone->region_shift);
+ nr_regions << clone->region_shift);
generic_make_request(bio);
} else
bio_endio(bio);
@@ -473,12 +480,21 @@ static void complete_discard_bio(struct clone *clone, struct bio *bio, bool succ
static void process_discard_bio(struct clone *clone, struct bio *bio)
{
- unsigned long rs, re;
+ unsigned long rs, nr_regions;
- bio_region_range(clone, bio, &rs, &re);
- BUG_ON(re > clone->nr_regions);
+ bio_region_range(clone, bio, &rs, &nr_regions);
+ if (!nr_regions) {
+ bio_endio(bio);
+ return;
+ }
- if (unlikely(rs == re)) {
+ if (WARN_ON(rs >= clone->nr_regions || (rs + nr_regions) < rs ||
+ (rs + nr_regions) > clone->nr_regions)) {
+ DMERR("%s: Invalid range (%lu + %lu, total regions %lu) for discard (%llu + %u)",
+ clone_device_name(clone), rs, nr_regions,
+ clone->nr_regions,
+ (unsigned long long)bio->bi_iter.bi_sector,
+ bio_sectors(bio));
bio_endio(bio);
return;
}
@@ -487,7 +503,7 @@ static void process_discard_bio(struct clone *clone, struct bio *bio)
* The covered regions are already hydrated so we just need to pass
* down the discard.
*/
- if (dm_clone_is_range_hydrated(clone->cmd, rs, re - rs)) {
+ if (dm_clone_is_range_hydrated(clone->cmd, rs, nr_regions)) {
complete_discard_bio(clone, bio, true);
return;
}
@@ -1169,7 +1185,7 @@ static void process_deferred_discards(struct clone *clone)
int r = -EPERM;
struct bio *bio;
struct blk_plug plug;
- unsigned long rs, re;
+ unsigned long rs, nr_regions;
struct bio_list discards = BIO_EMPTY_LIST;
spin_lock_irq(&clone->lock);
@@ -1185,14 +1201,13 @@ static void process_deferred_discards(struct clone *clone)
/* Update the metadata */
bio_list_for_each(bio, &discards) {
- bio_region_range(clone, bio, &rs, &re);
+ bio_region_range(clone, bio, &rs, &nr_regions);
/*
* A discard request might cover regions that have been already
* hydrated. There is no need to update the metadata for these
* regions.
*/
- r = dm_clone_cond_set_range(clone->cmd, rs, re - rs);
-
+ r = dm_clone_cond_set_range(clone->cmd, rs, nr_regions);
if (unlikely(r))
break;
}
This is a note to let you know that I've just added the patch titled
serial: sh-sci: Make sure status register SCxSR is read in correct
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 3dc4db3662366306e54ddcbda4804acb1258e4ba Mon Sep 17 00:00:00 2001
From: Kazuhiro Fujita <kazuhiro.fujita.jg(a)renesas.com>
Date: Fri, 27 Mar 2020 18:17:28 +0000
Subject: serial: sh-sci: Make sure status register SCxSR is read in correct
sequence
For SCIF and HSCIF interfaces the SCxSR register holds the status of
data that is to be read next from SCxRDR register, But where as for
SCIFA and SCIFB interfaces SCxSR register holds status of data that is
previously read from SCxRDR register.
This patch makes sure the status register is read depending on the port
types so that errors are caught accordingly.
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Kazuhiro Fujita <kazuhiro.fujita.jg(a)renesas.com>
Signed-off-by: Hao Bui <hao.bui.yg(a)renesas.com>
Signed-off-by: KAZUMI HARADA <kazumi.harada.rh(a)renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj(a)bp.renesas.com>
Tested-by: Geert Uytterhoeven <geert+renesas(a)glider.be>
Link: https://lore.kernel.org/r/1585333048-31828-1-git-send-email-kazuhiro.fujita…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/tty/serial/sh-sci.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index c073aa7001c4..e1179e74a2b8 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -870,9 +870,16 @@ static void sci_receive_chars(struct uart_port *port)
tty_insert_flip_char(tport, c, TTY_NORMAL);
} else {
for (i = 0; i < count; i++) {
- char c = serial_port_in(port, SCxRDR);
-
- status = serial_port_in(port, SCxSR);
+ char c;
+
+ if (port->type == PORT_SCIF ||
+ port->type == PORT_HSCIF) {
+ status = serial_port_in(port, SCxSR);
+ c = serial_port_in(port, SCxRDR);
+ } else {
+ c = serial_port_in(port, SCxRDR);
+ status = serial_port_in(port, SCxSR);
+ }
if (uart_handle_sysrq_char(port, c)) {
count--; i--;
continue;
--
2.26.1