The patch below does not apply to the 6.1-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>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 53dac345395c0d2493cbc2f4c85fe38aef5b63f5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021053-unranked-silt-0282@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 53dac345395c0d2493cbc2f4c85fe38aef5b63f5 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <frederic(a)kernel.org>
Date: Sat, 18 Jan 2025 00:24:33 +0100
Subject: [PATCH] hrtimers: Force migrate away hrtimers queued after
CPUHP_AP_HRTIMERS_DYING
hrtimers are migrated away from the dying CPU to any online target at
the CPUHP_AP_HRTIMERS_DYING stage in order not to delay bandwidth timers
handling tasks involved in the CPU hotplug forward progress.
However wakeups can still be performed by the outgoing CPU after
CPUHP_AP_HRTIMERS_DYING. Those can result again in bandwidth timers being
armed. Depending on several considerations (crystal ball power management
based election, earliest timer already enqueued, timer migration enabled or
not), the target may eventually be the current CPU even if offline. If that
happens, the timer is eventually ignored.
The most notable example is RCU which had to deal with each and every of
those wake-ups by deferring them to an online CPU, along with related
workarounds:
_ e787644caf76 (rcu: Defer RCU kthreads wakeup when CPU is dying)
_ 9139f93209d1 (rcu/nocb: Fix RT throttling hrtimer armed from offline CPU)
_ f7345ccc62a4 (rcu/nocb: Fix rcuog wake-up from offline softirq)
The problem isn't confined to RCU though as the stop machine kthread
(which runs CPUHP_AP_HRTIMERS_DYING) reports its completion at the end
of its work through cpu_stop_signal_done() and performs a wake up that
eventually arms the deadline server timer:
WARNING: CPU: 94 PID: 588 at kernel/time/hrtimer.c:1086 hrtimer_start_range_ns+0x289/0x2d0
CPU: 94 UID: 0 PID: 588 Comm: migration/94 Not tainted
Stopper: multi_cpu_stop+0x0/0x120 <- stop_machine_cpuslocked+0x66/0xc0
RIP: 0010:hrtimer_start_range_ns+0x289/0x2d0
Call Trace:
<TASK>
start_dl_timer
enqueue_dl_entity
dl_server_start
enqueue_task_fair
enqueue_task
ttwu_do_activate
try_to_wake_up
complete
cpu_stopper_thread
Instead of providing yet another bandaid to work around the situation, fix
it in the hrtimers infrastructure instead: always migrate away a timer to
an online target whenever it is enqueued from an offline CPU.
This will also allow to revert all the above RCU disgraceful hacks.
Fixes: 5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Reported-by: Vlad Poenaru <vlad.wing(a)gmail.com>
Reported-by: Usama Arif <usamaarif642(a)gmail.com>
Signed-off-by: Frederic Weisbecker <frederic(a)kernel.org>
Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: stable(a)vger.kernel.org
Tested-by: Paul E. McKenney <paulmck(a)kernel.org>
Link: https://lore.kernel.org/all/20250117232433.24027-1-frederic@kernel.org
Closes: 20241213203739.1519801-1-usamaarif642(a)gmail.com
diff --git a/include/linux/hrtimer_defs.h b/include/linux/hrtimer_defs.h
index c3b4b7ed7c16..84a5045f80f3 100644
--- a/include/linux/hrtimer_defs.h
+++ b/include/linux/hrtimer_defs.h
@@ -125,6 +125,7 @@ struct hrtimer_cpu_base {
ktime_t softirq_expires_next;
struct hrtimer *softirq_next_timer;
struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
+ call_single_data_t csd;
} ____cacheline_aligned;
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 4fb81f8c6f1c..deb1aa32814e 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -58,6 +58,8 @@
#define HRTIMER_ACTIVE_SOFT (HRTIMER_ACTIVE_HARD << MASK_SHIFT)
#define HRTIMER_ACTIVE_ALL (HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
+static void retrigger_next_event(void *arg);
+
/*
* The timer bases:
*
@@ -111,7 +113,8 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
.clockid = CLOCK_TAI,
.get_time = &ktime_get_clocktai,
},
- }
+ },
+ .csd = CSD_INIT(retrigger_next_event, NULL)
};
static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
@@ -124,6 +127,14 @@ static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
[CLOCK_TAI] = HRTIMER_BASE_TAI,
};
+static inline bool hrtimer_base_is_online(struct hrtimer_cpu_base *base)
+{
+ if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
+ return true;
+ else
+ return likely(base->online);
+}
+
/*
* Functions and macros which are different for UP/SMP systems are kept in a
* single place
@@ -178,27 +189,54 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
}
/*
- * We do not migrate the timer when it is expiring before the next
- * event on the target cpu. When high resolution is enabled, we cannot
- * reprogram the target cpu hardware and we would cause it to fire
- * late. To keep it simple, we handle the high resolution enabled and
- * disabled case similar.
+ * Check if the elected target is suitable considering its next
+ * event and the hotplug state of the current CPU.
+ *
+ * If the elected target is remote and its next event is after the timer
+ * to queue, then a remote reprogram is necessary. However there is no
+ * guarantee the IPI handling the operation would arrive in time to meet
+ * the high resolution deadline. In this case the local CPU becomes a
+ * preferred target, unless it is offline.
+ *
+ * High and low resolution modes are handled the same way for simplicity.
*
* Called with cpu_base->lock of target cpu held.
*/
-static int
-hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
+static bool hrtimer_suitable_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base,
+ struct hrtimer_cpu_base *new_cpu_base,
+ struct hrtimer_cpu_base *this_cpu_base)
{
ktime_t expires;
+ /*
+ * The local CPU clockevent can be reprogrammed. Also get_target_base()
+ * guarantees it is online.
+ */
+ if (new_cpu_base == this_cpu_base)
+ return true;
+
+ /*
+ * The offline local CPU can't be the default target if the
+ * next remote target event is after this timer. Keep the
+ * elected new base. An IPI will we issued to reprogram
+ * it as a last resort.
+ */
+ if (!hrtimer_base_is_online(this_cpu_base))
+ return true;
+
expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
- return expires < new_base->cpu_base->expires_next;
+
+ return expires >= new_base->cpu_base->expires_next;
}
-static inline
-struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
- int pinned)
+static inline struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base, int pinned)
{
+ if (!hrtimer_base_is_online(base)) {
+ int cpu = cpumask_any_and(cpu_online_mask, housekeeping_cpumask(HK_TYPE_TIMER));
+
+ return &per_cpu(hrtimer_bases, cpu);
+ }
+
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
if (static_branch_likely(&timers_migration_enabled) && !pinned)
return &per_cpu(hrtimer_bases, get_nohz_timer_target());
@@ -249,8 +287,8 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
raw_spin_unlock(&base->cpu_base->lock);
raw_spin_lock(&new_base->cpu_base->lock);
- if (new_cpu_base != this_cpu_base &&
- hrtimer_check_target(timer, new_base)) {
+ if (!hrtimer_suitable_target(timer, new_base, new_cpu_base,
+ this_cpu_base)) {
raw_spin_unlock(&new_base->cpu_base->lock);
raw_spin_lock(&base->cpu_base->lock);
new_cpu_base = this_cpu_base;
@@ -259,8 +297,7 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
}
WRITE_ONCE(timer->base, new_base);
} else {
- if (new_cpu_base != this_cpu_base &&
- hrtimer_check_target(timer, new_base)) {
+ if (!hrtimer_suitable_target(timer, new_base, new_cpu_base, this_cpu_base)) {
new_cpu_base = this_cpu_base;
goto again;
}
@@ -706,8 +743,6 @@ static inline int hrtimer_is_hres_enabled(void)
return hrtimer_hres_enabled;
}
-static void retrigger_next_event(void *arg);
-
/*
* Switch to high resolution mode
*/
@@ -1195,6 +1230,7 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
u64 delta_ns, const enum hrtimer_mode mode,
struct hrtimer_clock_base *base)
{
+ struct hrtimer_cpu_base *this_cpu_base = this_cpu_ptr(&hrtimer_bases);
struct hrtimer_clock_base *new_base;
bool force_local, first;
@@ -1206,9 +1242,15 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
* and enforce reprogramming after it is queued no matter whether
* it is the new first expiring timer again or not.
*/
- force_local = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
+ force_local = base->cpu_base == this_cpu_base;
force_local &= base->cpu_base->next_timer == timer;
+ /*
+ * Don't force local queuing if this enqueue happens on a unplugged
+ * CPU after hrtimer_cpu_dying() has been invoked.
+ */
+ force_local &= this_cpu_base->online;
+
/*
* Remove an active timer from the queue. In case it is not queued
* on the current CPU, make sure that remove_hrtimer() updates the
@@ -1238,8 +1280,27 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
}
first = enqueue_hrtimer(timer, new_base, mode);
- if (!force_local)
- return first;
+ if (!force_local) {
+ /*
+ * If the current CPU base is online, then the timer is
+ * never queued on a remote CPU if it would be the first
+ * expiring timer there.
+ */
+ if (hrtimer_base_is_online(this_cpu_base))
+ return first;
+
+ /*
+ * Timer was enqueued remote because the current base is
+ * already offline. If the timer is the first to expire,
+ * kick the remote CPU to reprogram the clock event.
+ */
+ if (first) {
+ struct hrtimer_cpu_base *new_cpu_base = new_base->cpu_base;
+
+ smp_call_function_single_async(new_cpu_base->cpu, &new_cpu_base->csd);
+ }
+ return 0;
+ }
/*
* Timer was forced to stay on the current CPU to avoid
The patch below does not apply to the 6.1-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>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 3e74859ee35edc33a022c3f3971df066ea0ca6b9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024123045-parka-sublet-a95d@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3e74859ee35edc33a022c3f3971df066ea0ca6b9 Mon Sep 17 00:00:00 2001
From: Boris Burkov <boris(a)bur.io>
Date: Fri, 13 Dec 2024 12:22:32 -0800
Subject: [PATCH] btrfs: check folio mapping after unlock in
relocate_one_folio()
When we call btrfs_read_folio() to bring a folio uptodate, we unlock the
folio. The result of that is that a different thread can modify the
mapping (like remove it with invalidate) before we call folio_lock().
This results in an invalid page and we need to try again.
In particular, if we are relocating concurrently with aborting a
transaction, this can result in a crash like the following:
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: 0000 [#1] SMP
CPU: 76 PID: 1411631 Comm: kworker/u322:5
Workqueue: events_unbound btrfs_reclaim_bgs_work
RIP: 0010:set_page_extent_mapped+0x20/0xb0
RSP: 0018:ffffc900516a7be8 EFLAGS: 00010246
RAX: ffffea009e851d08 RBX: ffffea009e0b1880 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffc900516a7b90 RDI: ffffea009e0b1880
RBP: 0000000003573000 R08: 0000000000000001 R09: ffff88c07fd2f3f0
R10: 0000000000000000 R11: 0000194754b575be R12: 0000000003572000
R13: 0000000003572fff R14: 0000000000100cca R15: 0000000005582fff
FS: 0000000000000000(0000) GS:ffff88c07fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000407d00f002 CR4: 00000000007706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
? __die+0x78/0xc0
? page_fault_oops+0x2a8/0x3a0
? __switch_to+0x133/0x530
? wq_worker_running+0xa/0x40
? exc_page_fault+0x63/0x130
? asm_exc_page_fault+0x22/0x30
? set_page_extent_mapped+0x20/0xb0
relocate_file_extent_cluster+0x1a7/0x940
relocate_data_extent+0xaf/0x120
relocate_block_group+0x20f/0x480
btrfs_relocate_block_group+0x152/0x320
btrfs_relocate_chunk+0x3d/0x120
btrfs_reclaim_bgs_work+0x2ae/0x4e0
process_scheduled_works+0x184/0x370
worker_thread+0xc6/0x3e0
? blk_add_timer+0xb0/0xb0
kthread+0xae/0xe0
? flush_tlb_kernel_range+0x90/0x90
ret_from_fork+0x2f/0x40
? flush_tlb_kernel_range+0x90/0x90
ret_from_fork_asm+0x11/0x20
</TASK>
This occurs because cleanup_one_transaction() calls
destroy_delalloc_inodes() which calls invalidate_inode_pages2() which
takes the folio_lock before setting mapping to NULL. We fail to check
this, and subsequently call set_extent_mapping(), which assumes that
mapping != NULL (in fact it asserts that in debug mode)
Note that the "fixes" patch here is not the one that introduced the
race (the very first iteration of this code from 2009) but a more recent
change that made this particular crash happen in practice.
Fixes: e7f1326cc24e ("btrfs: set page extent mapped after read_folio in relocate_one_page")
CC: stable(a)vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu(a)suse.com>
Signed-off-by: Boris Burkov <boris(a)bur.io>
Signed-off-by: David Sterba <dsterba(a)suse.com>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index bf267bdfa8f8..db8b42f674b7 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2902,6 +2902,7 @@ static int relocate_one_folio(struct reloc_control *rc,
const bool use_rst = btrfs_need_stripe_tree_update(fs_info, rc->block_group->flags);
ASSERT(index <= last_index);
+again:
folio = filemap_lock_folio(inode->i_mapping, index);
if (IS_ERR(folio)) {
@@ -2937,6 +2938,11 @@ static int relocate_one_folio(struct reloc_control *rc,
ret = -EIO;
goto release_folio;
}
+ if (folio->mapping != inode->i_mapping) {
+ folio_unlock(folio);
+ folio_put(folio);
+ goto again;
+ }
}
/*
The patch below does not apply to the 6.6-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>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 3e74859ee35edc33a022c3f3971df066ea0ca6b9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024123042-limelight-doily-8703@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3e74859ee35edc33a022c3f3971df066ea0ca6b9 Mon Sep 17 00:00:00 2001
From: Boris Burkov <boris(a)bur.io>
Date: Fri, 13 Dec 2024 12:22:32 -0800
Subject: [PATCH] btrfs: check folio mapping after unlock in
relocate_one_folio()
When we call btrfs_read_folio() to bring a folio uptodate, we unlock the
folio. The result of that is that a different thread can modify the
mapping (like remove it with invalidate) before we call folio_lock().
This results in an invalid page and we need to try again.
In particular, if we are relocating concurrently with aborting a
transaction, this can result in a crash like the following:
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: 0000 [#1] SMP
CPU: 76 PID: 1411631 Comm: kworker/u322:5
Workqueue: events_unbound btrfs_reclaim_bgs_work
RIP: 0010:set_page_extent_mapped+0x20/0xb0
RSP: 0018:ffffc900516a7be8 EFLAGS: 00010246
RAX: ffffea009e851d08 RBX: ffffea009e0b1880 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffc900516a7b90 RDI: ffffea009e0b1880
RBP: 0000000003573000 R08: 0000000000000001 R09: ffff88c07fd2f3f0
R10: 0000000000000000 R11: 0000194754b575be R12: 0000000003572000
R13: 0000000003572fff R14: 0000000000100cca R15: 0000000005582fff
FS: 0000000000000000(0000) GS:ffff88c07fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000407d00f002 CR4: 00000000007706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
? __die+0x78/0xc0
? page_fault_oops+0x2a8/0x3a0
? __switch_to+0x133/0x530
? wq_worker_running+0xa/0x40
? exc_page_fault+0x63/0x130
? asm_exc_page_fault+0x22/0x30
? set_page_extent_mapped+0x20/0xb0
relocate_file_extent_cluster+0x1a7/0x940
relocate_data_extent+0xaf/0x120
relocate_block_group+0x20f/0x480
btrfs_relocate_block_group+0x152/0x320
btrfs_relocate_chunk+0x3d/0x120
btrfs_reclaim_bgs_work+0x2ae/0x4e0
process_scheduled_works+0x184/0x370
worker_thread+0xc6/0x3e0
? blk_add_timer+0xb0/0xb0
kthread+0xae/0xe0
? flush_tlb_kernel_range+0x90/0x90
ret_from_fork+0x2f/0x40
? flush_tlb_kernel_range+0x90/0x90
ret_from_fork_asm+0x11/0x20
</TASK>
This occurs because cleanup_one_transaction() calls
destroy_delalloc_inodes() which calls invalidate_inode_pages2() which
takes the folio_lock before setting mapping to NULL. We fail to check
this, and subsequently call set_extent_mapping(), which assumes that
mapping != NULL (in fact it asserts that in debug mode)
Note that the "fixes" patch here is not the one that introduced the
race (the very first iteration of this code from 2009) but a more recent
change that made this particular crash happen in practice.
Fixes: e7f1326cc24e ("btrfs: set page extent mapped after read_folio in relocate_one_page")
CC: stable(a)vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu(a)suse.com>
Signed-off-by: Boris Burkov <boris(a)bur.io>
Signed-off-by: David Sterba <dsterba(a)suse.com>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index bf267bdfa8f8..db8b42f674b7 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2902,6 +2902,7 @@ static int relocate_one_folio(struct reloc_control *rc,
const bool use_rst = btrfs_need_stripe_tree_update(fs_info, rc->block_group->flags);
ASSERT(index <= last_index);
+again:
folio = filemap_lock_folio(inode->i_mapping, index);
if (IS_ERR(folio)) {
@@ -2937,6 +2938,11 @@ static int relocate_one_folio(struct reloc_control *rc,
ret = -EIO;
goto release_folio;
}
+ if (folio->mapping != inode->i_mapping) {
+ folio_unlock(folio);
+ folio_put(folio);
+ goto again;
+ }
}
/*
In the page to order 0 folio conversion series, the commit
7e119cff9d0a, "ocfs2: convert w_pages to w_folios" and
commit 9a5e08652dc4b, "ocfs2: use an array of folios
instead of an array of pages", saves -ENOMEM in the
folio array upon allocation failure and calls the folio
array free code. The folio array free code expects either
valid folio pointers or NULL. Finding the -ENOMEM will
result in a panic. Fix by NULLing the error folio entry.
Signed-off-by: Mark Tinguely <mark.tinguely(a)oracle.com>
Cc: stable(a)vger.kernel.org
Cc: Changwei Ge <gechangwei(a)live.cn>
Cc: Joel Becker <jlbec(a)evilplan.org>
Cc: Junxiao Bi <junxiao.bi(a)oracle.com>
Cc: Mark Fasheh <mark(a)fasheh.com>
Cc: Matthew Wilcox <willy(a)infradead.org>
---
v2: sorry, ocfs2_grab_folios() needs the same change.
the other callers do not need the change.
---
fs/ocfs2/alloc.c | 1 +
fs/ocfs2/aops.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index b8ac85b548c7..821cb7874685 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -6918,6 +6918,7 @@ static int ocfs2_grab_folios(struct inode *inode,
loff_t start, loff_t end,
if (IS_ERR(folios[numfolios])) {
ret = PTR_ERR(folios[numfolios]);
mlog_errno(ret);
+ folios[numfolios] = NULL;
goto out;
}
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 40b6bce12951..89aadc6cdd87 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1071,6 +1071,7 @@ static int ocfs2_grab_folios_for_write(struct
address_space *mapping,
if (IS_ERR(wc->w_folios[i])) {
ret = PTR_ERR(wc->w_folios[i]);
mlog_errno(ret);
+ wc->w_folios[i] = NULL;
goto out;
}
}
--
2.39.5 (Apple Git-154)
This patch series aims to fix various issues throughout the QinHeng CH9200
driver. This driver fails to handle various failures, which in one
case has lead to a uninit access bug found via syzbot. Upon reviewing
the driver I fixed a few more issues which I have included in this patch
series.
Parts of this series are the product of discussions and suggestions I had
from others like Andrew Lunn, Simon Horman and Jakub Kicinski you can view those
discussions below:
Link: <https://lore.kernel.org/all/20250319112156.48312-1-qasdev00@gmail.com>
Link: <https://lore.kernel.org/all/20250218002443.11731-1-qasdev00@gmail.com/>
Link: <https://lore.kernel.org/all/20250311161157.49065-1-qasdev00@gmail.com/>
Qasim Ijaz (5):
fix uninitialised access bug during mii_nway_restart
remove extraneous return that prevents error propagation
fail fast on control_read() failures during get_mac_address()
add missing error handling in ch9200_bind()
avoid triggering NWay restart on non-zero PHY ID
drivers/net/usb/ch9200.c | 61 ++++++++++++++++++++++++++--------------
1 file changed, 40 insertions(+), 21 deletions(-)
--
2.39.5
Add the missing memory barrier to make sure that the REO dest ring
descriptor is read after the head pointer to avoid using stale data on
weakly ordered architectures like aarch64.
This may fix the ring-buffer corruption worked around by commit
f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination
ring") by silently discarding data, and may possibly also address user
reported errors like:
ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set
Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41
Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Cc: stable(a)vger.kernel.org # 5.6
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218005
Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org>
---
As I reported here:
https://lore.kernel.org/lkml/Z9G5zEOcTdGKm7Ei@hovoldconsulting.com/
the ath11k and ath12k appear to be missing a number of memory barriers
that are required on weakly ordered architectures like aarch64 to avoid
memory corruption issues.
Here's a fix for one more such case which people already seem to be
hitting.
Note that I've seen one "msdu_done" bit not set warning also with this
patch so whether it helps with that at all remains to be seen. I'm CCing
Jens and Steev that see these warnings frequently and that may be able
to help out with testing.
Johan
drivers/net/wireless/ath/ath11k/dp_rx.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
index 029ecf51c9ef..0a57b337e4c6 100644
--- a/drivers/net/wireless/ath/ath11k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
@@ -2646,7 +2646,7 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
struct ath11k *ar;
struct hal_reo_dest_ring *desc;
enum hal_reo_dest_ring_push_reason push_reason;
- u32 cookie;
+ u32 cookie, info0, rx_msdu_info0, rx_mpdu_info0;
int i;
for (i = 0; i < MAX_RADIOS; i++)
@@ -2659,11 +2659,14 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
try_again:
ath11k_hal_srng_access_begin(ab, srng);
+ /* Make sure descriptor is read after the head pointer. */
+ dma_rmb();
+
while (likely(desc =
(struct hal_reo_dest_ring *)ath11k_hal_srng_dst_get_next_entry(ab,
srng))) {
cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
- desc->buf_addr_info.info1);
+ READ_ONCE(desc->buf_addr_info.info1));
buf_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_BUF_ID,
cookie);
mac_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_PDEV_ID, cookie);
@@ -2692,8 +2695,9 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
num_buffs_reaped[mac_id]++;
+ info0 = READ_ONCE(desc->info0);
push_reason = FIELD_GET(HAL_REO_DEST_RING_INFO0_PUSH_REASON,
- desc->info0);
+ info0);
if (unlikely(push_reason !=
HAL_REO_DEST_RING_PUSH_REASON_ROUTING_INSTRUCTION)) {
dev_kfree_skb_any(msdu);
@@ -2701,18 +2705,21 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
continue;
}
- rxcb->is_first_msdu = !!(desc->rx_msdu_info.info0 &
+ rx_msdu_info0 = READ_ONCE(desc->rx_msdu_info.info0);
+ rx_mpdu_info0 = READ_ONCE(desc->rx_mpdu_info.info0);
+
+ rxcb->is_first_msdu = !!(rx_msdu_info0 &
RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU);
- rxcb->is_last_msdu = !!(desc->rx_msdu_info.info0 &
+ rxcb->is_last_msdu = !!(rx_msdu_info0 &
RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU);
- rxcb->is_continuation = !!(desc->rx_msdu_info.info0 &
+ rxcb->is_continuation = !!(rx_msdu_info0 &
RX_MSDU_DESC_INFO0_MSDU_CONTINUATION);
rxcb->peer_id = FIELD_GET(RX_MPDU_DESC_META_DATA_PEER_ID,
- desc->rx_mpdu_info.meta_data);
+ READ_ONCE(desc->rx_mpdu_info.meta_data));
rxcb->seq_no = FIELD_GET(RX_MPDU_DESC_INFO0_SEQ_NUM,
- desc->rx_mpdu_info.info0);
+ rx_mpdu_info0);
rxcb->tid = FIELD_GET(HAL_REO_DEST_RING_INFO0_RX_QUEUE_NUM,
- desc->info0);
+ info0);
rxcb->mac_id = mac_id;
__skb_queue_tail(&msdu_list[mac_id], msdu);
--
2.48.1
Users of the Lenovo ThinkPad X13s have reported that Wi-Fi sometimes
breaks and the log fills up with errors like:
ath11k_pci 0006:01:00.0: HTC Rx: insufficient length, got 1484, expected 1492
ath11k_pci 0006:01:00.0: HTC Rx: insufficient length, got 1460, expected 1484
which based on a quick look at the driver seemed to indicate some kind
of ring-buffer corruption.
Miaoqing Pan tracked it down to the host seeing the updated destination
ring head pointer before the updated descriptor, and the error handling
for that in turn leaves the ring buffer in an inconsistent state.
Add the missing memory barrier to make sure that the descriptor is read
after the head pointer to address the root cause of the corruption while
fixing up the error handling in case there are ever any (ordering) bugs
on the device side.
Note that the READ_ONCE() are only needed to avoid compiler mischief in
case the ring-buffer helpers are ever inlined.
Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41
Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218623
Link: https://lore.kernel.org/20250310010217.3845141-3-quic_miaoqing@quicinc.com
Cc: Miaoqing Pan <quic_miaoqing(a)quicinc.com>
Cc: stable(a)vger.kernel.org # 5.6
Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org>
---
drivers/net/wireless/ath/ath11k/ce.c | 11 +++++------
drivers/net/wireless/ath/ath11k/hal.c | 4 ++--
2 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/drivers/net/wireless/ath/ath11k/ce.c b/drivers/net/wireless/ath/ath11k/ce.c
index e66e86bdec20..9d8efec46508 100644
--- a/drivers/net/wireless/ath/ath11k/ce.c
+++ b/drivers/net/wireless/ath/ath11k/ce.c
@@ -393,11 +393,10 @@ static int ath11k_ce_completed_recv_next(struct ath11k_ce_pipe *pipe,
goto err;
}
+ /* Make sure descriptor is read after the head pointer. */
+ dma_rmb();
+
*nbytes = ath11k_hal_ce_dst_status_get_length(desc);
- if (*nbytes == 0) {
- ret = -EIO;
- goto err;
- }
*skb = pipe->dest_ring->skb[sw_index];
pipe->dest_ring->skb[sw_index] = NULL;
@@ -430,8 +429,8 @@ static void ath11k_ce_recv_process_cb(struct ath11k_ce_pipe *pipe)
dma_unmap_single(ab->dev, ATH11K_SKB_RXCB(skb)->paddr,
max_nbytes, DMA_FROM_DEVICE);
- if (unlikely(max_nbytes < nbytes)) {
- ath11k_warn(ab, "rxed more than expected (nbytes %d, max %d)",
+ if (unlikely(max_nbytes < nbytes || nbytes == 0)) {
+ ath11k_warn(ab, "unexpected rx length (nbytes %d, max %d)",
nbytes, max_nbytes);
dev_kfree_skb_any(skb);
continue;
diff --git a/drivers/net/wireless/ath/ath11k/hal.c b/drivers/net/wireless/ath/ath11k/hal.c
index 61f4b6dd5380..8cb1505a5a0c 100644
--- a/drivers/net/wireless/ath/ath11k/hal.c
+++ b/drivers/net/wireless/ath/ath11k/hal.c
@@ -599,7 +599,7 @@ u32 ath11k_hal_ce_dst_status_get_length(void *buf)
struct hal_ce_srng_dst_status_desc *desc = buf;
u32 len;
- len = FIELD_GET(HAL_CE_DST_STATUS_DESC_FLAGS_LEN, desc->flags);
+ len = FIELD_GET(HAL_CE_DST_STATUS_DESC_FLAGS_LEN, READ_ONCE(desc->flags));
desc->flags &= ~HAL_CE_DST_STATUS_DESC_FLAGS_LEN;
return len;
@@ -829,7 +829,7 @@ void ath11k_hal_srng_access_begin(struct ath11k_base *ab, struct hal_srng *srng)
srng->u.src_ring.cached_tp =
*(volatile u32 *)srng->u.src_ring.tp_addr;
} else {
- srng->u.dst_ring.cached_hp = *srng->u.dst_ring.hp_addr;
+ srng->u.dst_ring.cached_hp = READ_ONCE(*srng->u.dst_ring.hp_addr);
/* Try to prefetch the next descriptor in the ring */
if (srng->flags & HAL_SRNG_FLAGS_CACHED)
--
2.48.1
Embryo socket is not queued in gc_candidates, so we can't drop
a reference held by its oob_skb.
Let's say we create listener and embryo sockets, send the
listener's fd to the embryo as OOB data, and close() them
without recv()ing the OOB data.
There is a self-reference cycle like
listener -> embryo.oob_skb -> listener
, so this must be cleaned up by GC. Otherwise, the listener's
refcnt is not released and sockets are leaked:
# unshare -n
# cat /proc/net/protocols | grep UNIX-STREAM
UNIX-STREAM 1024 0 -1 NI 0 yes kernel ...
# python3
>>> from array import array
>>> from socket import *
>>>
>>> s = socket(AF_UNIX, SOCK_STREAM)
>>> s.bind('\0test\0')
>>> s.listen()
>>>
>>> c = socket(AF_UNIX, SOCK_STREAM)
>>> c.connect(s.getsockname())
>>> c.sendmsg([b'x'], [(SOL_SOCKET, SCM_RIGHTS, array('i', [s.fileno()]))], MSG_OOB)
1
>>> quit()
# cat /proc/net/protocols | grep UNIX-STREAM
UNIX-STREAM 1024 3 -1 NI 0 yes kernel ...
^^^
3 sockets still in use after FDs are close()d
Let's drop the embryo socket's oob_skb ref in scan_inflight().
This also fixes a racy access to oob_skb that commit 9841991a446c
("af_unix: Update unix_sk(sk)->oob_skb under sk_receive_queue
lock.") fixed for the new Tarjan's algo-based GC.
Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Reported-by: Lei Lu <llfamsec(a)gmail.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu(a)amazon.com>
---
This has no upstream commit because I replaced the entire GC in
6.10 and the new GC does not have this bug, and this fix is only
applicable to the old GC (<= 6.9), thus for 5.15/6.1/6.6.
---
---
net/unix/garbage.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index 2a758531e102..b3fbdf129944 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -102,13 +102,14 @@ static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *),
/* Process the descriptors of this socket */
int nfd = UNIXCB(skb).fp->count;
struct file **fp = UNIXCB(skb).fp->fp;
+ struct unix_sock *u;
while (nfd--) {
/* Get the socket the fd matches if it indeed does so */
struct sock *sk = unix_get_socket(*fp++);
if (sk) {
- struct unix_sock *u = unix_sk(sk);
+ u = unix_sk(sk);
/* Ignore non-candidates, they could
* have been added to the queues after
@@ -122,6 +123,13 @@ static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *),
}
}
if (hit && hitlist != NULL) {
+#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
+ u = unix_sk(x);
+ if (u->oob_skb) {
+ WARN_ON_ONCE(skb_unref(u->oob_skb));
+ u->oob_skb = NULL;
+ }
+#endif
__skb_unlink(skb, &x->sk_receive_queue);
__skb_queue_tail(hitlist, skb);
}
@@ -299,17 +307,9 @@ void unix_gc(void)
* which are creating the cycle(s).
*/
skb_queue_head_init(&hitlist);
- list_for_each_entry(u, &gc_candidates, link) {
+ list_for_each_entry(u, &gc_candidates, link)
scan_children(&u->sk, inc_inflight, &hitlist);
-#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
- if (u->oob_skb) {
- kfree_skb(u->oob_skb);
- u->oob_skb = NULL;
- }
-#endif
- }
-
/* not_cycle_list contains those sockets which do not make up a
* cycle. Restore these to the inflight list.
*/
--
2.39.5 (Apple Git-154)