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authorGao Xiang <hsiangkao@linux.alibaba.com>2024-07-22 05:51:10 +0200
committerGao Xiang <hsiangkao@linux.alibaba.com>2024-07-26 12:47:33 +0200
commit7dc5537c3f8be87e005f0844a7626c987914f8fd (patch)
tree0de42dc2bb9c72d3d5e17621470a83ccb8294d6d /fs
parenterofs: support STATX_DIOALIGN (diff)
downloadlinux-7dc5537c3f8be87e005f0844a7626c987914f8fd.tar.xz
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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.c3
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)