[syzbot] [mm?] [cgroups?] kernel BUG in swap_cgroup_record (2)

[syzbot] [mm?] [cgroups?] kernel BUG in swap_cgroup_record (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    f8f97927abf7 Add linux-next specific files for 20260105
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=131ff69a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a0672dd8d69c3235
dashboard link: https://syzkaller.appspot.com/bug?extid=d97580a8cceb9b03c13e
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17065efc580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=176c9e9a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1837bbc8e23e/disk-f8f97927.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/07390717f7e4/vmlinux-f8f97927.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f4a72ec80dc/bzImage-f8f97927.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at mm/swap_cgroup.c:78!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6176 Comm: syz.0.30 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
Code: 02 e9 6d ff ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 35 ff ff ff 4c 89 f7 e8 cf 84 f6 ff e9 28 ff ff ff e8 e5 c1 8f ff 90 <0f> 0b e8 dd c1 8f ff 4c 89 f7 48 c7 c6 80 f6 98 8b e8 de d4 f6 fe
RSP: 0018:ffffc90003176720 EFLAGS: 00010093
RAX: ffffffff8231359b RBX: 0000000000001b88 RCX: ffff8880351f9e40
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200062ecd4 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffc900041b1000 R15: 0000000000000002
FS:  00007feeba18f6c0(0000) GS:ffff8881259c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feeba18ef98 CR3: 0000000077742000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 memcg1_swapout+0x2fa/0x830 mm/memcontrol-v1.c:623
 __remove_mapping+0xac5/0xe30 mm/vmscan.c:773
 shrink_folio_list+0x2786/0x4f40 mm/vmscan.c:1528
 reclaim_folio_list+0xeb/0x4e0 mm/vmscan.c:2208
 reclaim_pages+0x454/0x520 mm/vmscan.c:2245
 madvise_cold_or_pageout_pte_range+0x19a0/0x1ce0 mm/madvise.c:563
 walk_pmd_range mm/pagewalk.c:130 [inline]
 walk_pud_range mm/pagewalk.c:224 [inline]
 walk_p4d_range mm/pagewalk.c:262 [inline]
 walk_pgd_range+0x1037/0x1d30 mm/pagewalk.c:303
 __walk_page_range+0x14c/0x710 mm/pagewalk.c:410
 walk_page_range_vma_unsafe+0x34c/0x400 mm/pagewalk.c:714
 madvise_pageout_page_range mm/madvise.c:622 [inline]
 madvise_pageout mm/madvise.c:647 [inline]
 madvise_vma_behavior+0x3132/0x4170 mm/madvise.c:1366
 madvise_walk_vmas+0x575/0xaf0 mm/madvise.c:1721
 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1937
 do_madvise+0x1bc/0x270 mm/madvise.c:2030
 __do_sys_madvise mm/madvise.c:2039 [inline]
 __se_sys_madvise mm/madvise.c:2037 [inline]
 __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:2037
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feeb938f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007feeba18f038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007feeb95e6090 RCX: 00007feeb938f749
RDX: 0000000000000015 RSI: 0000000000800000 RDI: 0000200000000000
RBP: 00007feeb9413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feeb95e6128 R14: 00007feeb95e6090 R15: 00007ffd48399048
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
Code: 02 e9 6d ff ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 35 ff ff ff 4c 89 f7 e8 cf 84 f6 ff e9 28 ff ff ff e8 e5 c1 8f ff 90 <0f> 0b e8 dd c1 8f ff 4c 89 f7 48 c7 c6 80 f6 98 8b e8 de d4 f6 fe
RSP: 0018:ffffc90003176720 EFLAGS: 00010093
RAX: ffffffff8231359b RBX: 0000000000001b88 RCX: ffff8880351f9e40
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200062ecd4 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffc900041b1000 R15: 0000000000000002
FS:  00007feeba18f6c0(0000) GS:ffff8881259c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feeba18ef98 CR3: 0000000077742000 CR4: 00000000003526f0


---
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Forwarded: [PATCH] mm/swap_cgroup: fix kernel BUG in swap_cgroup_record

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] mm/swap_cgroup: fix kernel BUG in swap_cgroup_record
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

When using MADV_PAGEOUT, pages can remain in swapcache with their swap
entries assigned. If MADV_PAGEOUT is called again on these pages, they
reuse the same swap entries, causing memcg1_swapout() to call
swap_cgroup_record() with an already-recorded entry.

The existing code assumes swap entries are always being recorded for the
first time (oldid == 0), triggering VM_BUG_ON when it encounters an
already-recorded entry:

  ------------[ cut here ]------------
  kernel BUG at mm/swap_cgroup.c:78!
  Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
  CPU: 0 UID: 0 PID: 6176 Comm: syz.0.30 Not tainted
  RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
  Call Trace:
   memcg1_swapout+0x2fa/0x830 mm/memcontrol-v1.c:623
   __remove_mapping+0xac5/0xe30 mm/vmscan.c:773
   shrink_folio_list+0x2786/0x4f40 mm/vmscan.c:1528
   reclaim_folio_list+0xeb/0x4e0 mm/vmscan.c:2208
   reclaim_pages+0x454/0x520 mm/vmscan.c:2245
   madvise_cold_or_pageout_pte_range+0x19a0/0x1ce0 mm/madvise.c:563
   ...
   do_madvise+0x1bc/0x270 mm/madvise.c:2030
   __do_sys_madvise mm/madvise.c:2039

This bug occurs because pages in swapcache can be targeted by
MADV_PAGEOUT multiple times without being swapped in between. Each time,
the same swap entry is reused, but swap_cgroup_record() expects to only
record new, unused entries.

Fix this by checking if the swap entry already has the correct cgroup ID
recorded before attempting to record it. Add a new helper function
swap_cgroup_lookup() to read the current cgroup ID without modifying it.
In memcg1_swapout(), check if the entry is already correctly recorded and
return early if so, avoiding unnecessary work and the crash. Only call
swap_cgroup_record() when the entry needs to be set or updated.

This approach is more efficient than making swap_cgroup_record()
idempotent, as it avoids unnecessary atomic operations, reference count
manipulations, and statistics updates when the entry is already correct.

Link: https://syzkaller.appspot.com/bug?extid=d97580a8cceb9b03c13e
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 include/linux/swap_cgroup.h |  6 ++++++
 mm/memcontrol-v1.c          |  7 +++++++
 mm/swap_cgroup.c            | 18 ++++++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/include/linux/swap_cgroup.h b/include/linux/swap_cgroup.h
index 91cdf12190a0..fd79e7bf8917 100644
--- a/include/linux/swap_cgroup.h
+++ b/include/linux/swap_cgroup.h
@@ -7,6 +7,7 @@
 #if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP)
 
 extern void swap_cgroup_record(struct folio *folio, unsigned short id, swp_entry_t ent);
+extern unsigned short swap_cgroup_lookup(swp_entry_t ent);
 extern unsigned short swap_cgroup_clear(swp_entry_t ent, unsigned int nr_ents);
 extern unsigned short lookup_swap_cgroup_id(swp_entry_t ent);
 extern int swap_cgroup_swapon(int type, unsigned long max_pages);
@@ -19,6 +20,11 @@ void swap_cgroup_record(struct folio *folio, unsigned short id, swp_entry_t ent)
 {
 }
 
+static inline unsigned short swap_cgroup_lookup(swp_entry_t ent)
+{
+	return 0;
+}
+
 static inline
 unsigned short swap_cgroup_clear(swp_entry_t ent, unsigned int nr_ents)
 {
diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 56d27baf93ab..37899d156b2a 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -614,6 +614,7 @@ void memcg1_swapout(struct folio *folio, swp_entry_t entry)
 {
 	struct mem_cgroup *memcg, *swap_memcg;
 	unsigned int nr_entries;
+	unsigned short oldid;
 
 	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
 	VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
@@ -630,6 +631,12 @@ void memcg1_swapout(struct folio *folio, swp_entry_t entry)
 	if (!memcg)
 		return;
 
+	oldid = swap_cgroup_lookup(entry);
+	if (oldid == mem_cgroup_id(memcg)) {
+		return;
+	}
+	VM_WARN_ON_ONCE(oldid != 0);
+
 	/*
 	 * In case the memcg owning these pages has been offlined and doesn't
 	 * have an ID allocated to it anymore, charge the closest online
diff --git a/mm/swap_cgroup.c b/mm/swap_cgroup.c
index de779fed8c21..083eda4b67d6 100644
--- a/mm/swap_cgroup.c
+++ b/mm/swap_cgroup.c
@@ -51,6 +51,24 @@ static unsigned short __swap_cgroup_id_xchg(struct swap_cgroup *map,
 	return old_id;
 }
 
+unsigned short swap_cgroup_lookup(swp_entry_t ent)
+{
+	struct swap_cgroup *sc;
+	unsigned short id;
+	pgoff_t offset = swp_offset(ent);
+	unsigned short type = swp_type(ent);
+
+	if (type >= MAX_SWAPFILES)
+		return 0;
+
+	sc = swap_cgroup_ctrl[type].map;
+	if (!sc)
+		return 0;
+	id = (unsigned short)atomic_read(&sc[offset].ids);
+	return id;
+
+}
+
 /**
  * swap_cgroup_record - record mem_cgroup for a set of swap entries.
  * These entries must belong to one single folio, and that folio
-- 
2.43.0

Forwarded: [PATCH] mm/swap_cgroup: fix kernel BUG in swap_cgroup_record

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] mm/swap_cgroup: fix kernel BUG in swap_cgroup_record
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

When using MADV_PAGEOUT, pages can remain in swapcache with their swap
entries assigned. If MADV_PAGEOUT is called again on these pages, they
reuse the same swap entries, causing memcg1_swapout() to call
swap_cgroup_record() with an already-recorded entry.

The existing code assumes swap entries are always being recorded for the
first time (oldid == 0), triggering VM_BUG_ON when it encounters an
already-recorded entry:

  ------------[ cut here ]------------
  kernel BUG at mm/swap_cgroup.c:78!
  Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
  CPU: 0 UID: 0 PID: 6176 Comm: syz.0.30 Not tainted
  RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
  Call Trace:
   memcg1_swapout+0x2fa/0x830 mm/memcontrol-v1.c:623
   __remove_mapping+0xac5/0xe30 mm/vmscan.c:773
   shrink_folio_list+0x2786/0x4f40 mm/vmscan.c:1528
   reclaim_folio_list+0xeb/0x4e0 mm/vmscan.c:2208
   reclaim_pages+0x454/0x520 mm/vmscan.c:2245
   madvise_cold_or_pageout_pte_range+0x19a0/0x1ce0 mm/madvise.c:563
   ...
   do_madvise+0x1bc/0x270 mm/madvise.c:2030
   __do_sys_madvise mm/madvise.c:2039

This bug occurs because pages in swapcache can be targeted by
MADV_PAGEOUT multiple times without being swapped in between. Each time,
the same swap entry is reused, but swap_cgroup_record() expects to only
record new, unused entries.

Fix this by checking if the swap entry already has the correct cgroup ID
recorded before attempting to record it. Use the existing
lookup_swap_cgroup_id() to read the current cgroup ID, and return early
from memcg1_swapout() if the entry is already correctly recorded. Only
call swap_cgroup_record() when the entry needs to be set or updated.

This approach avoids unnecessary atomic operations, reference count
manipulations, and statistics updates when the entry is already correct.

Link: https://syzkaller.appspot.com/bug?extid=d97580a8cceb9b03c13e
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 mm/memcontrol-v1.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 56d27baf93ab..982cfe5af225 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -614,6 +614,7 @@ void memcg1_swapout(struct folio *folio, swp_entry_t entry)
 {
 	struct mem_cgroup *memcg, *swap_memcg;
 	unsigned int nr_entries;
+	unsigned short oldid;
 
 	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
 	VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
@@ -630,6 +631,16 @@ void memcg1_swapout(struct folio *folio, swp_entry_t entry)
 	if (!memcg)
 		return;
 
+	/*
+	 * Check if this swap entry is already recorded. This can happen
+	 * when MADV_PAGEOUT is called multiple times on pages that remain
+	 * in swapcache, reusing the same swap entries.
+	 */
+	oldid = lookup_swap_cgroup_id(entry);
+	if (oldid == mem_cgroup_id(memcg))
+		return;
+	VM_WARN_ON_ONCE(oldid != 0);
+
 	/*
 	 * In case the memcg owning these pages has been offlined and doesn't
 	 * have an ID allocated to it anymore, charge the closest online
-- 
2.43.0

Forwarded: [PATCH] mm/swap_cgroup: fix kernel BUG in swap_cgroup_record

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] mm/swap_cgroup: fix kernel BUG in swap_cgroup_record
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

When using MADV_PAGEOUT, pages can remain in swapcache with their swap
entries assigned. If MADV_PAGEOUT is called again on these pages, they
reuse the same swap entries, causing memcg1_swapout() to call
swap_cgroup_record() with an already-recorded entry.

The existing code assumes swap entries are always being recorded for the
first time (oldid == 0), triggering VM_BUG_ON when it encounters an
already-recorded entry:

  ------------[ cut here ]------------
  kernel BUG at mm/swap_cgroup.c:78!
  Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
  CPU: 0 UID: 0 PID: 6176 Comm: syz.0.30 Not tainted
  RIP: 0010:swap_cgroup_record+0x19c/0x1c0 mm/swap_cgroup.c:78
  Call Trace:
   memcg1_swapout+0x2fa/0x830 mm/memcontrol-v1.c:623
   __remove_mapping+0xac5/0xe30 mm/vmscan.c:773
   shrink_folio_list+0x2786/0x4f40 mm/vmscan.c:1528
   reclaim_folio_list+0xeb/0x4e0 mm/vmscan.c:2208
   reclaim_pages+0x454/0x520 mm/vmscan.c:2245
   madvise_cold_or_pageout_pte_range+0x19a0/0x1ce0 mm/madvise.c:563
   ...
   do_madvise+0x1bc/0x270 mm/madvise.c:2030
   __do_sys_madvise mm/madvise.c:2039

This bug occurs because pages in swapcache can be targeted by
MADV_PAGEOUT multiple times without being swapped in between. Each time,
the same swap entry is reused, but swap_cgroup_record() expects to only
record new, unused entries.

Fix this by checking if the swap entry already has the correct cgroup ID
recorded before attempting to record it. Use the existing
lookup_swap_cgroup_id() to read the current cgroup ID, and return early
from memcg1_swapout() if the entry is already correctly recorded. Only
call swap_cgroup_record() when the entry needs to be set or updated.

This approach avoids unnecessary atomic operations, reference count
manipulations, and statistics updates when the entry is already correct.

Link: https://syzkaller.appspot.com/bug?extid=d97580a8cceb9b03c13e
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 mm/memcontrol-v1.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 56d27baf93ab..982cfe5af225 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -614,6 +614,7 @@ void memcg1_swapout(struct folio *folio, swp_entry_t entry)
 {
 	struct mem_cgroup *memcg, *swap_memcg;
 	unsigned int nr_entries;
+	unsigned short oldid;
 
 	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
 	VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
@@ -630,6 +631,16 @@ void memcg1_swapout(struct folio *folio, swp_entry_t entry)
 	if (!memcg)
 		return;
 
+	/*
+	 * Check if this swap entry is already recorded. This can happen
+	 * when MADV_PAGEOUT is called multiple times on pages that remain
+	 * in swapcache, reusing the same swap entries.
+	 */
+	oldid = lookup_swap_cgroup_id(entry);
+	if (oldid == mem_cgroup_id(memcg))
+		return;
+	VM_WARN_ON_ONCE(oldid != 0);
+
 	/*
 	 * In case the memcg owning these pages has been offlined and doesn't
 	 * have an ID allocated to it anymore, charge the closest online
-- 
2.43.0

Forwarded: [PATCH] mm, swap: fix cgroup V1 leak after removal of swap cache bypass

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] mm, swap: fix cgroup V1 leak after removal of swap cache bypass
Author: ryncsn@gmail.com

From: Kairui Song <kasong@tencent.com>

#syz test

Recent patch is causing a memory cgruop V1 swap leak, this patch should
fix that [1].

Link: https://lore.kernel.org/all/CAMgjq7CMsAMZZJL1=a=EtfWCOuDFE62RKR_0hUdPC4H+QF5GfQ@mail.gmail.com/ [1]
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/6960c2f0.050a0220.1c677c.03be.GAE@google.com/
Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f35afc5093dc..a0e3f51de749 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -760,8 +760,8 @@ static int __remove_mapping(struct address_space *mapping, struct folio *folio,
 
 		if (reclaimed && !mapping_exiting(mapping))
 			shadow = workingset_eviction(folio, target_memcg);
-		__swap_cache_del_folio(ci, folio, swap, shadow);
 		memcg1_swapout(folio, swap);
+		__swap_cache_del_folio(ci, folio, swap, shadow);
 		swap_cluster_unlock_irq(ci);
 	} else {
 		void (*free_folio)(struct folio *);
-- 
2.52.0

Forwarded: [PATCH] mm, swap: fix cgroup V1 leak after removal of swap cache bypass

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] mm, swap: fix cgroup V1 leak after removal of swap cache bypass
Author: ryncsn@gmail.com

From: Kairui Song <kasong@tencent.com>

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

Recent patch is causing a memory cgruop V1 swap leak, this patch should
fix that [1].

Link: https://lore.kernel.org/all/CAMgjq7CMsAMZZJL1=a=EtfWCOuDFE62RKR_0hUdPC4H+QF5GfQ@mail.gmail.com/ [1]
Reported-by: syzbot+d97580a8cceb9b03c13e@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/6960c2f0.050a0220.1c677c.03be.GAE@google.com/
Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f35afc5093dc..a0e3f51de749 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -760,8 +760,8 @@ static int __remove_mapping(struct address_space *mapping, struct folio *folio,
 
 		if (reclaimed && !mapping_exiting(mapping))
 			shadow = workingset_eviction(folio, target_memcg);
-		__swap_cache_del_folio(ci, folio, swap, shadow);
 		memcg1_swapout(folio, swap);
+		__swap_cache_del_folio(ci, folio, swap, shadow);
 		swap_cluster_unlock_irq(ci);
 	} else {
 		void (*free_folio)(struct folio *);
-- 
2.52.0