The patch titled
Subject: mm/sparse.c: reset section's mem_map when fully deactivated
has been removed from the -mm tree. Its filename was
mm-sparse-reset-sections-mem_map-when-fully-deactivated.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Pingfan Liu <kernelfans(a)gmail.com>
Subject: mm/sparse.c: reset section's mem_map when fully deactivated
After commit ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug"),
when a mem section is fully deactivated, section_mem_map still records the
section's start pfn, which is not used any more and will be reassigned
during re-addition.
In analogy with alloc/free pattern, it is better to clear all fields of
section_mem_map.
Beside this, it breaks the user space tool "makedumpfile" [1], which makes
assumption that a hot-removed section has mem_map as NULL, instead of
checking directly against SECTION_MARKED_PRESENT bit. (makedumpfile will
be better to change the assumption, and need a patch)
The bug can be reproduced on IBM POWERVM by "drmgr -c mem -r -q 5" ,
trigger a crash, and save vmcore by makedumpfile
[1]: makedumpfile, commit e73016540293 ("[v1.6.7] Update version")
Link: http://lkml.kernel.org/r/1579487594-28889-1-git-send-email-kernelfans@gmail…
Signed-off-by: Pingfan Liu <kernelfans(a)gmail.com>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Acked-by: David Hildenbrand <david(a)redhat.com>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Oscar Salvador <osalvador(a)suse.de>
Cc: Baoquan He <bhe(a)redhat.com>
Cc: Qian Cai <cai(a)lca.pw>
Cc: Kazuhito Hagio <k-hagio(a)ab.jp.nec.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/sparse.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/sparse.c~mm-sparse-reset-sections-mem_map-when-fully-deactivated
+++ a/mm/sparse.c
@@ -789,7 +789,7 @@ static void section_deactivate(unsigned
ms->usage = NULL;
}
memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
- ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr);
+ ms->section_mem_map = (unsigned long)NULL;
}
if (section_is_early && memmap)
_
Patches currently in -mm which might be from kernelfans(a)gmail.com are
The patch titled
Subject: mm/mempolicy.c: fix out of bounds write in mpol_parse_str()
has been removed from the -mm tree. Its filename was
mm-mempolicyc-fix-out-of-bounds-write-in-mpol_parse_str.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Dan Carpenter <dan.carpenter(a)oracle.com>
Subject: mm/mempolicy.c: fix out of bounds write in mpol_parse_str()
What we are trying to do is change the '=' character to a NUL terminator
and then at the end of the function we restore it back to an '='. The
problem is there are two error paths where we jump to the end of the
function before we have replaced the '=' with NUL. We end up putting the
'=' in the wrong place (possibly one element before the start of the
buffer).
Link: http://lkml.kernel.org/r/20200115055426.vdjwvry44nfug7yy@kili.mountain
Reported-by: syzbot+e64a13c5369a194d67df(a)syzkaller.appspotmail.com
Fixes: 095f1fc4ebf3 ("mempolicy: rework shmem mpol parsing and display")
Signed-off-by: Dan Carpenter <dan.carpenter(a)oracle.com>
Acked-by: Vlastimil Babka <vbabka(a)suse.cz>
Dmitry Vyukov <dvyukov(a)google.com>
Cc: Michal Hocko <mhocko(a)kernel.org>
Cc: Dan Carpenter <dan.carpenter(a)oracle.com>
Cc: Lee Schermerhorn <lee.schermerhorn(a)hp.com>
Cc: Andrea Arcangeli <aarcange(a)redhat.com>
Cc: Hugh Dickins <hughd(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/mempolicy.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicyc-fix-out-of-bounds-write-in-mpol_parse_str
+++ a/mm/mempolicy.c
@@ -2821,6 +2821,9 @@ int mpol_parse_str(char *str, struct mem
char *flags = strchr(str, '=');
int err = 1, mode;
+ if (flags)
+ *flags++ = '\0'; /* terminate mode string */
+
if (nodelist) {
/* NUL-terminate mode or flags string */
*nodelist++ = '\0';
@@ -2831,9 +2834,6 @@ int mpol_parse_str(char *str, struct mem
} else
nodes_clear(nodes);
- if (flags)
- *flags++ = '\0'; /* terminate mode string */
-
mode = match_string(policy_modes, MPOL_MAX, str);
if (mode < 0)
goto out;
_
Patches currently in -mm which might be from dan.carpenter(a)oracle.com are
The patch titled
Subject: memcg: fix a crash in wb_workfn when a device disappears
has been removed from the -mm tree. Its filename was
memcg-fix-a-crash-in-wb_workfn-when-a-device-disappears.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: "Theodore Ts'o" <tytso(a)mit.edu>
Subject: memcg: fix a crash in wb_workfn when a device disappears
Without memcg, there is a one-to-one mapping between the bdi and
bdi_writeback structures. In this world, things are fairly
straightforward; the first thing bdi_unregister() does is to shutdown the
bdi_writeback structure (or wb), and part of that writeback ensures that
no other work queued against the wb, and that the wb is fully drained.
With memcg, however, there is a one-to-many relationship between the bdi
and bdi_writeback structures; that is, there are multiple wb objects which
can all point to a single bdi. There is a refcount which prevents the bdi
object from being released (and hence, unregistered). So in theory, the
bdi_unregister() *should* only get called once its refcount goes to zero
(bdi_put will drop the refcount, and when it is zero, release_bdi gets
called, which calls bdi_unregister).
Unfortunately, del_gendisk() in block/gen_hd.c never got the memo about
the Brave New memcg World, and calls bdi_unregister directly. It does
this without informing the file system, or the memcg code, or anything
else. This causes the root wb associated with the bdi to be unregistered,
but none of the memcg-specific wb's are shutdown. So when one of these
wb's are woken up to do delayed work, they try to dereference their
wb->bdi->dev to fetch the device name, but unfortunately bdi->dev is now
NULL, thanks to the bdi_unregister() called by del_gendisk(). As a
result, *boom*.
Fortunately, it looks like the rest of the writeback path is perfectly
happy with bdi->dev and bdi->owner being NULL, so the simplest fix is to
create a bdi_dev_name() function which can handle bdi->dev being NULL.
This also allows us to bulletproof the writeback tracepoints to prevent
them from dereferencing a NULL pointer and crashing the kernel if one is
tracing with memcg's enabled, and an iSCSI device dies or a USB storage
stick is pulled.
The most common way of triggering this will be hotremoval of a device
while writeback with memcg enabled is going on. It was triggering several
times a day in a heavily loaded production environment.
Google Bug Id: 145475544
Link: https://lore.kernel.org/r/20191227194829.150110-1-tytso@mit.edu
Link: http://lkml.kernel.org/r/20191228005211.163952-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Cc: Chris Mason <clm(a)fb.com>
Cc: Tejun Heo <tj(a)kernel.org>
Cc: Jens Axboe <axboe(a)kernel.dk>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/fs-writeback.c | 2 -
include/linux/backing-dev.h | 10 +++++++
include/trace/events/writeback.h | 37 +++++++++++++----------------
mm/backing-dev.c | 1
4 files changed, 29 insertions(+), 21 deletions(-)
--- a/fs/fs-writeback.c~memcg-fix-a-crash-in-wb_workfn-when-a-device-disappears
+++ a/fs/fs-writeback.c
@@ -2063,7 +2063,7 @@ void wb_workfn(struct work_struct *work)
struct bdi_writeback, dwork);
long pages_written;
- set_worker_desc("flush-%s", dev_name(wb->bdi->dev));
+ set_worker_desc("flush-%s", bdi_dev_name(wb->bdi));
current->flags |= PF_SWAPWRITE;
if (likely(!current_is_workqueue_rescuer() ||
--- a/include/linux/backing-dev.h~memcg-fix-a-crash-in-wb_workfn-when-a-device-disappears
+++ a/include/linux/backing-dev.h
@@ -13,6 +13,7 @@
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/blkdev.h>
+#include <linux/device.h>
#include <linux/writeback.h>
#include <linux/blk-cgroup.h>
#include <linux/backing-dev-defs.h>
@@ -504,4 +505,13 @@ static inline int bdi_rw_congested(struc
(1 << WB_async_congested));
}
+extern const char *bdi_unknown_name;
+
+static inline const char *bdi_dev_name(struct backing_dev_info *bdi)
+{
+ if (!bdi || !bdi->dev)
+ return bdi_unknown_name;
+ return dev_name(bdi->dev);
+}
+
#endif /* _LINUX_BACKING_DEV_H */
--- a/include/trace/events/writeback.h~memcg-fix-a-crash-in-wb_workfn-when-a-device-disappears
+++ a/include/trace/events/writeback.h
@@ -67,8 +67,8 @@ DECLARE_EVENT_CLASS(writeback_page_templ
TP_fast_assign(
strscpy_pad(__entry->name,
- mapping ? dev_name(inode_to_bdi(mapping->host)->dev) : "(unknown)",
- 32);
+ bdi_dev_name(mapping ? inode_to_bdi(mapping->host) :
+ NULL), 32);
__entry->ino = mapping ? mapping->host->i_ino : 0;
__entry->index = page->index;
),
@@ -111,8 +111,7 @@ DECLARE_EVENT_CLASS(writeback_dirty_inod
struct backing_dev_info *bdi = inode_to_bdi(inode);
/* may be called for files on pseudo FSes w/ unregistered bdi */
- strscpy_pad(__entry->name,
- bdi->dev ? dev_name(bdi->dev) : "(unknown)", 32);
+ strscpy_pad(__entry->name, bdi_dev_name(bdi), 32);
__entry->ino = inode->i_ino;
__entry->state = inode->i_state;
__entry->flags = flags;
@@ -193,7 +192,7 @@ TRACE_EVENT(inode_foreign_history,
),
TP_fast_assign(
- strncpy(__entry->name, dev_name(inode_to_bdi(inode)->dev), 32);
+ strncpy(__entry->name, bdi_dev_name(inode_to_bdi(inode)), 32);
__entry->ino = inode->i_ino;
__entry->cgroup_ino = __trace_wbc_assign_cgroup(wbc);
__entry->history = history;
@@ -222,7 +221,7 @@ TRACE_EVENT(inode_switch_wbs,
),
TP_fast_assign(
- strncpy(__entry->name, dev_name(old_wb->bdi->dev), 32);
+ strncpy(__entry->name, bdi_dev_name(old_wb->bdi), 32);
__entry->ino = inode->i_ino;
__entry->old_cgroup_ino = __trace_wb_assign_cgroup(old_wb);
__entry->new_cgroup_ino = __trace_wb_assign_cgroup(new_wb);
@@ -255,7 +254,7 @@ TRACE_EVENT(track_foreign_dirty,
struct address_space *mapping = page_mapping(page);
struct inode *inode = mapping ? mapping->host : NULL;
- strncpy(__entry->name, dev_name(wb->bdi->dev), 32);
+ strncpy(__entry->name, bdi_dev_name(wb->bdi), 32);
__entry->bdi_id = wb->bdi->id;
__entry->ino = inode ? inode->i_ino : 0;
__entry->memcg_id = wb->memcg_css->id;
@@ -288,7 +287,7 @@ TRACE_EVENT(flush_foreign,
),
TP_fast_assign(
- strncpy(__entry->name, dev_name(wb->bdi->dev), 32);
+ strncpy(__entry->name, bdi_dev_name(wb->bdi), 32);
__entry->cgroup_ino = __trace_wb_assign_cgroup(wb);
__entry->frn_bdi_id = frn_bdi_id;
__entry->frn_memcg_id = frn_memcg_id;
@@ -318,7 +317,7 @@ DECLARE_EVENT_CLASS(writeback_write_inod
TP_fast_assign(
strscpy_pad(__entry->name,
- dev_name(inode_to_bdi(inode)->dev), 32);
+ bdi_dev_name(inode_to_bdi(inode)), 32);
__entry->ino = inode->i_ino;
__entry->sync_mode = wbc->sync_mode;
__entry->cgroup_ino = __trace_wbc_assign_cgroup(wbc);
@@ -361,9 +360,7 @@ DECLARE_EVENT_CLASS(writeback_work_class
__field(ino_t, cgroup_ino)
),
TP_fast_assign(
- strscpy_pad(__entry->name,
- wb->bdi->dev ? dev_name(wb->bdi->dev) :
- "(unknown)", 32);
+ strscpy_pad(__entry->name, bdi_dev_name(wb->bdi), 32);
__entry->nr_pages = work->nr_pages;
__entry->sb_dev = work->sb ? work->sb->s_dev : 0;
__entry->sync_mode = work->sync_mode;
@@ -416,7 +413,7 @@ DECLARE_EVENT_CLASS(writeback_class,
__field(ino_t, cgroup_ino)
),
TP_fast_assign(
- strscpy_pad(__entry->name, dev_name(wb->bdi->dev), 32);
+ strscpy_pad(__entry->name, bdi_dev_name(wb->bdi), 32);
__entry->cgroup_ino = __trace_wb_assign_cgroup(wb);
),
TP_printk("bdi %s: cgroup_ino=%lu",
@@ -438,7 +435,7 @@ TRACE_EVENT(writeback_bdi_register,
__array(char, name, 32)
),
TP_fast_assign(
- strscpy_pad(__entry->name, dev_name(bdi->dev), 32);
+ strscpy_pad(__entry->name, bdi_dev_name(bdi), 32);
),
TP_printk("bdi %s",
__entry->name
@@ -463,7 +460,7 @@ DECLARE_EVENT_CLASS(wbc_class,
),
TP_fast_assign(
- strscpy_pad(__entry->name, dev_name(bdi->dev), 32);
+ strscpy_pad(__entry->name, bdi_dev_name(bdi), 32);
__entry->nr_to_write = wbc->nr_to_write;
__entry->pages_skipped = wbc->pages_skipped;
__entry->sync_mode = wbc->sync_mode;
@@ -514,7 +511,7 @@ TRACE_EVENT(writeback_queue_io,
),
TP_fast_assign(
unsigned long *older_than_this = work->older_than_this;
- strscpy_pad(__entry->name, dev_name(wb->bdi->dev), 32);
+ strscpy_pad(__entry->name, bdi_dev_name(wb->bdi), 32);
__entry->older = older_than_this ? *older_than_this : 0;
__entry->age = older_than_this ?
(jiffies - *older_than_this) * 1000 / HZ : -1;
@@ -600,7 +597,7 @@ TRACE_EVENT(bdi_dirty_ratelimit,
),
TP_fast_assign(
- strscpy_pad(__entry->bdi, dev_name(wb->bdi->dev), 32);
+ strscpy_pad(__entry->bdi, bdi_dev_name(wb->bdi), 32);
__entry->write_bw = KBps(wb->write_bandwidth);
__entry->avg_write_bw = KBps(wb->avg_write_bandwidth);
__entry->dirty_rate = KBps(dirty_rate);
@@ -665,7 +662,7 @@ TRACE_EVENT(balance_dirty_pages,
TP_fast_assign(
unsigned long freerun = (thresh + bg_thresh) / 2;
- strscpy_pad(__entry->bdi, dev_name(wb->bdi->dev), 32);
+ strscpy_pad(__entry->bdi, bdi_dev_name(wb->bdi), 32);
__entry->limit = global_wb_domain.dirty_limit;
__entry->setpoint = (global_wb_domain.dirty_limit +
@@ -726,7 +723,7 @@ TRACE_EVENT(writeback_sb_inodes_requeue,
TP_fast_assign(
strscpy_pad(__entry->name,
- dev_name(inode_to_bdi(inode)->dev), 32);
+ bdi_dev_name(inode_to_bdi(inode)), 32);
__entry->ino = inode->i_ino;
__entry->state = inode->i_state;
__entry->dirtied_when = inode->dirtied_when;
@@ -800,7 +797,7 @@ DECLARE_EVENT_CLASS(writeback_single_ino
TP_fast_assign(
strscpy_pad(__entry->name,
- dev_name(inode_to_bdi(inode)->dev), 32);
+ bdi_dev_name(inode_to_bdi(inode)), 32);
__entry->ino = inode->i_ino;
__entry->state = inode->i_state;
__entry->dirtied_when = inode->dirtied_when;
--- a/mm/backing-dev.c~memcg-fix-a-crash-in-wb_workfn-when-a-device-disappears
+++ a/mm/backing-dev.c
@@ -21,6 +21,7 @@ struct backing_dev_info noop_backing_dev
EXPORT_SYMBOL_GPL(noop_backing_dev_info);
static struct class *bdi_class;
+const char *bdi_unknown_name = "(unknown)";
/*
* bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU
_
Patches currently in -mm which might be from tytso(a)mit.edu are