diff options
| author | Gao Xiang <hsiangkao@linux.alibaba.com> | 2024-07-22 11:51:10 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2024-07-26 18:47:33 +0800 |
| commit | 7dc5537c3f8be87e005f0844a7626c987914f8fd (patch) | |
| tree | 0de42dc2bb9c72d3d5e17621470a83ccb8294d6d /fs | |
| parent | 9c421ef3f6b30ab912eaaa3c3d20cfb921fd8c8f (diff) | |
| download | lwn-7dc5537c3f8be87e005f0844a7626c987914f8fd.tar.gz lwn-7dc5537c3f8be87e005f0844a7626c987914f8fd.zip | |
erofs: fix race in z_erofs_get_gbuf()
In z_erofs_get_gbuf(), the current task may be migrated to another
CPU between `z_erofs_gbuf_id()` and `spin_lock(&gbuf->lock)`.
Therefore, z_erofs_put_gbuf() will trigger the following issue
which was found by stress test:
<2>[772156.434168] kernel BUG at fs/erofs/zutil.c:58!
..
<4>[772156.435007]
<4>[772156.439237] CPU: 0 PID: 3078 Comm: stress Kdump: loaded Tainted: G E 6.10.0-rc7+ #2
<4>[772156.439239] Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 1.0.0 01/01/2017
<4>[772156.439241] pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
<4>[772156.439243] pc : z_erofs_put_gbuf+0x64/0x70 [erofs]
<4>[772156.439252] lr : z_erofs_lz4_decompress+0x600/0x6a0 [erofs]
..
<6>[772156.445958] stress (3127): drop_caches: 1
<4>[772156.446120] Call trace:
<4>[772156.446121] z_erofs_put_gbuf+0x64/0x70 [erofs]
<4>[772156.446761] z_erofs_lz4_decompress+0x600/0x6a0 [erofs]
<4>[772156.446897] z_erofs_decompress_queue+0x740/0xa10 [erofs]
<4>[772156.447036] z_erofs_runqueue+0x428/0x8c0 [erofs]
<4>[772156.447160] z_erofs_readahead+0x224/0x390 [erofs]
..
Fixes: f36f3010f676 ("erofs: rename per-CPU buffers to global buffer pool and make it configurable")
Cc: <stable@vger.kernel.org> # 6.10+
Reviewed-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Sandeep Dhavale <dhavale@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240722035110.3456740-1-hsiangkao@linux.alibaba.com
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/erofs/zutil.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/erofs/zutil.c b/fs/erofs/zutil.c index b80f612867c2..9b53883e5caf 100644 --- a/fs/erofs/zutil.c +++ b/fs/erofs/zutil.c @@ -38,11 +38,13 @@ void *z_erofs_get_gbuf(unsigned int requiredpages) { struct z_erofs_gbuf *gbuf; + migrate_disable(); gbuf = &z_erofs_gbufpool[z_erofs_gbuf_id()]; spin_lock(&gbuf->lock); /* check if the buffer is too small */ if (requiredpages > gbuf->nrpages) { spin_unlock(&gbuf->lock); + migrate_enable(); /* (for sparse checker) pretend gbuf->lock is still taken */ __acquire(gbuf->lock); return NULL; @@ -57,6 +59,7 @@ void z_erofs_put_gbuf(void *ptr) __releases(gbuf->lock) gbuf = &z_erofs_gbufpool[z_erofs_gbuf_id()]; DBG_BUGON(gbuf->ptr != ptr); spin_unlock(&gbuf->lock); + migrate_enable(); } int z_erofs_gbuf_growsize(unsigned int nrpages) |