[PATCH 5.17 0885/1126] f2fs: use spin_lock to avoid hang

Greg Kroah-Hartman
2022-04-05T09:08:29Z

From: Jaegeuk Kim <jaegeuk@kernel.org>

[ Upstream commit 98237fcda4a24e67b0a4498c17d5aa4ad4537bc7 ]

[14696.634553] task:cat state:D stack: 0 pid:1613738 ppid:1613735 flags:0x00000004
[14696.638285] Call Trace:
[14696.639038] <TASK>
[14696.640032] __schedule+0x302/0x930
[14696.640969] schedule+0x58/0xd0
[14696.641799] schedule_preempt_disabled+0x18/0x30
[14696.642890] __mutex_lock.constprop.0+0x2fb/0x4f0
[14696.644035] ? mod_objcg_state+0x10c/0x310
[14696.645040] ? obj_cgroup_charge+0xe1/0x170
[14696.646067] __mutex_lock_slowpath+0x13/0x20
[14696.647126] mutex_lock+0x34/0x40
[14696.648070] stat_show+0x25/0x17c0 [f2fs]
[14696.649218] seq_read_iter+0x120/0x4b0
[14696.650289] ? aa_file_perm+0x12a/0x500
[14696.651357] ? lru_cache_add+0x1c/0x20
[14696.652470] seq_read+0xfd/0x140
[14696.653445] full_proxy_read+0x5c/0x80
[14696.654535] vfs_read+0xa0/0x1a0
[14696.655497] ksys_read+0x67/0xe0
[14696.656502] __x64_sys_read+0x1a/0x20
[14696.657580] do_syscall_64+0x3b/0xc0
[14696.658671] entry_SYSCALL_64_after_hwframe+0x44/0xae
[14696.660068] RIP: 0033:0x7efe39df1cb2
[14696.661133] RSP: 002b:00007ffc8badd948 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[14696.662958] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007efe39df1cb2
[14696.664757] RDX: 0000000000020000 RSI: 00007efe399df000 RDI: 0000000000000003
[14696.666542] RBP: 00007efe399df000 R08: 00007efe399de010 R09: 00007efe399de010
[14696.668363] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000000000
[14696.670155] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
[14696.671965] </TASK>
[14696.672826] task:umount state:D stack: 0 pid:1614985 ppid:1614984 flags:0x00004000
[14696.674930] Call Trace:
[14696.675903] <TASK>
[14696.676780] __schedule+0x302/0x930
[14696.677927] schedule+0x58/0xd0
[14696.679019] schedule_preempt_disabled+0x18/0x30
[14696.680412] __mutex_lock.constprop.0+0x2fb/0x4f0
[14696.681783] ? destroy_inode+0x65/0x80
[14696.683006] __mutex_lock_slowpath+0x13/0x20
[14696.684305] mutex_lock+0x34/0x40
[14696.685442] f2fs_destroy_stats+0x1e/0x60 [f2fs]
[14696.686803] f2fs_put_super+0x158/0x390 [f2fs]
[14696.688238] generic_shutdown_super+0x7a/0x120
[14696.689621] kill_block_super+0x27/0x50
[14696.690894] kill_f2fs_super+0x7f/0x100 [f2fs]
[14696.692311] deactivate_locked_super+0x35/0xa0
[14696.693698] deactivate_super+0x40/0x50
[14696.694985] cleanup_mnt+0x139/0x190
[14696.696209] __cleanup_mnt+0x12/0x20
[14696.697390] task_work_run+0x64/0xa0
[14696.698587] exit_to_user_mode_prepare+0x1b7/0x1c0
[14696.700053] syscall_exit_to_user_mode+0x27/0x50
[14696.701418] do_syscall_64+0x48/0xc0
[14696.702630] entry_SYSCALL_64_after_hwframe+0x44/0xae

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/debug.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index 07ad0d81f0c5..b449c7a372a4 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -21,7 +21,7 @@
#include "gc.h"

static LIST_HEAD(f2fs_stat_list);
-static DEFINE_MUTEX(f2fs_stat_mutex);
+static DEFINE_RAW_SPINLOCK(f2fs_stat_lock);
#ifdef CONFIG_DEBUG_FS
static struct dentry *f2fs_debugfs_root;
#endif
@@ -345,8 +345,9 @@ static int stat_show(struct seq_file *s, void *v)
{
struct f2fs_stat_info *si;
int i = 0, j = 0;
+ unsigned long flags;

- mutex_lock(&f2fs_stat_mutex);
+ raw_spin_lock_irqsave(&f2fs_stat_lock, flags);
list_for_each_entry(si, &f2fs_stat_list, stat_list) {
update_general_status(si->sbi);

@@ -574,7 +575,7 @@ static int stat_show(struct seq_file *s, void *v)
seq_printf(s, " - paged : %llu KB\n",
si->page_mem >> 10);
}
- mutex_unlock(&f2fs_stat_mutex);
+ raw_spin_unlock_irqrestore(&f2fs_stat_lock, flags);
return 0;
}

@@ -585,6 +586,7 @@ int f2fs_build_stats(struct f2fs_sb_info *sbi)
{
struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
struct f2fs_stat_info *si;
+ unsigned long flags;
int i;

si = f2fs_kzalloc(sbi, sizeof(struct f2fs_stat_info), GFP_KERNEL);
@@ -620,9 +622,9 @@ int f2fs_build_stats(struct f2fs_sb_info *sbi)
atomic_set(&sbi->max_aw_cnt, 0);
atomic_set(&sbi->max_vw_cnt, 0);

- mutex_lock(&f2fs_stat_mutex);
+ raw_spin_lock_irqsave(&f2fs_stat_lock, flags);
list_add_tail(&si->stat_list, &f2fs_stat_list);
- mutex_unlock(&f2fs_stat_mutex);
+ raw_spin_unlock_irqrestore(&f2fs_stat_lock, flags);

return 0;
}
@@ -630,10 +632,11 @@ int f2fs_build_stats(struct f2fs_sb_info *sbi)
void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
{
struct f2fs_stat_info *si = F2FS_STAT(sbi);
+ unsigned long flags;

- mutex_lock(&f2fs_stat_mutex);
+ raw_spin_lock_irqsave(&f2fs_stat_lock, flags);
list_del(&si->stat_list);
- mutex_unlock(&f2fs_stat_mutex);
+ raw_spin_unlock_irqrestore(&f2fs_stat_lock, flags);

kfree(si);
}
--
2.34.1