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author | Barry Song <v-songbaohua@oppo.com> | 2024-03-19 12:47:06 +1300 |
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committer | Andrew Morton <akpm@linux-foundation.org> | 2024-03-26 11:07:21 -0700 |
commit | 9c500835f279e636722bbcafdfe62cc0153ec292 (patch) | |
tree | f2210e697206d16e731ef8ef390f4accd5b84e96 | |
parent | c52eb6db7b7dd8b4b338b16c5c37df22a6b08fdf (diff) | |
download | linux-stable-9c500835f279e636722bbcafdfe62cc0153ec292.tar.gz linux-stable-9c500835f279e636722bbcafdfe62cc0153ec292.tar.bz2 linux-stable-9c500835f279e636722bbcafdfe62cc0153ec292.zip |
mm: zswap: fix kernel BUG in sg_init_one
sg_init_one() relies on linearly mapped low memory for the safe
utilization of virt_to_page(). Otherwise, we trigger a kernel BUG,
kernel BUG at include/linux/scatterlist.h:187!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 2997 Comm: syz-executor198 Not tainted 6.8.0-syzkaller #0
Hardware name: ARM-Versatile Express
PC is at sg_set_buf include/linux/scatterlist.h:187 [inline]
PC is at sg_init_one+0x9c/0xa8 lib/scatterlist.c:143
LR is at sg_init_table+0x2c/0x40 lib/scatterlist.c:128
Backtrace:
[<807e16ac>] (sg_init_one) from [<804c1824>] (zswap_decompress+0xbc/0x208 mm/zswap.c:1089)
r7:83471c80 r6:def6d08c r5:844847d0 r4:ff7e7ef4
[<804c1768>] (zswap_decompress) from [<804c4468>] (zswap_load+0x15c/0x198 mm/zswap.c:1637)
r9:8446eb80 r8:8446eb80 r7:8446eb84 r6:def6d08c r5:00000001 r4:844847d0
[<804c430c>] (zswap_load) from [<804b9644>] (swap_read_folio+0xa8/0x498 mm/page_io.c:518)
r9:844ac800 r8:835e6c00 r7:00000000 r6:df955d4c r5:00000001 r4:def6d08c
[<804b959c>] (swap_read_folio) from [<804bb064>] (swap_cluster_readahead+0x1c4/0x34c mm/swap_state.c:684)
r10:00000000 r9:00000007 r8:df955d4b r7:00000000 r6:00000000 r5:00100cca
r4:00000001
[<804baea0>] (swap_cluster_readahead) from [<804bb3b8>] (swapin_readahead+0x68/0x4a8 mm/swap_state.c:904)
r10:df955eb8 r9:00000000 r8:00100cca r7:84476480 r6:00000001 r5:00000000
r4:00000001
[<804bb350>] (swapin_readahead) from [<8047cde0>] (do_swap_page+0x200/0xcc4 mm/memory.c:4046)
r10:00000040 r9:00000000 r8:844ac800 r7:84476480 r6:00000001 r5:00000000
r4:df955eb8
[<8047cbe0>] (do_swap_page) from [<8047e6c4>] (handle_pte_fault mm/memory.c:5301 [inline])
[<8047cbe0>] (do_swap_page) from [<8047e6c4>] (__handle_mm_fault mm/memory.c:5439 [inline])
[<8047cbe0>] (do_swap_page) from [<8047e6c4>] (handle_mm_fault+0x3d8/0x12b8 mm/memory.c:5604)
r10:00000040 r9:842b3900 r8:7eb0d000 r7:84476480 r6:7eb0d000 r5:835e6c00
r4:00000254
[<8047e2ec>] (handle_mm_fault) from [<80215d28>] (do_page_fault+0x148/0x3a8 arch/arm/mm/fault.c:326)
r10:00000007 r9:842b3900 r8:7eb0d000 r7:00000207 r6:00000254 r5:7eb0d9b4
r4:df955fb0
[<80215be0>] (do_page_fault) from [<80216170>] (do_DataAbort+0x38/0xa8 arch/arm/mm/fault.c:558)
r10:7eb0da7c r9:00000000 r8:80215be0 r7:df955fb0 r6:7eb0d9b4 r5:00000207
r4:8261d0e0
[<80216138>] (do_DataAbort) from [<80200e3c>] (__dabt_usr+0x5c/0x60 arch/arm/kernel/entry-armv.S:427)
Exception stack(0xdf955fb0 to 0xdf955ff8)
5fa0: 00000000 00000000 22d5f800 0008d158
5fc0: 00000000 7eb0d9a4 00000000 00000109 00000000 00000000 7eb0da7c 7eb0da3c
5fe0: 00000000 7eb0d9a0 00000001 00066bd4 00000010 ffffffff
r8:824a9044 r7:835e6c00 r6:ffffffff r5:00000010 r4:00066bd4
Code: 1a000004 e1822003 e8860094 e89da8f0 (e7f001f2)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 1a000004 bne 0x18
4: e1822003 orr r2, r2, r3
8: e8860094 stm r6, {r2, r4, r7}
c: e89da8f0 ldm sp, {r4, r5, r6, r7, fp, sp, pc}
* 10: e7f001f2 udf #18 <-- trapping instruction
Consequently, we have two choices: either employ kmap_to_page() alongside
sg_set_page(), or resort to copying high memory contents to a temporary
buffer residing in low memory. However, considering the introduction of
the WARN_ON_ONCE in commit ef6e06b2ef870 ("highmem: fix kmap_to_page() for
kmap_local_page() addresses"), which specifically addresses high memory
concerns, it appears that memcpy remains the sole viable option.
Link: https://lkml.kernel.org/r/20240318234706.95347-1-21cnbao@gmail.com
Fixes: 270700dd06ca ("mm/zswap: remove the memcpy if acomp is not sleepable")
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reported-by: syzbot+adbc983a1588b7805de3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000bbb3d80613f243a6@google.com/
Tested-by: syzbot+adbc983a1588b7805de3@syzkaller.appspotmail.com
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r-- | mm/zswap.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 9dec853647c8..fc2755b05a73 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1080,7 +1080,17 @@ static void zswap_decompress(struct zswap_entry *entry, struct page *page) mutex_lock(&acomp_ctx->mutex); src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO); - if (acomp_ctx->is_sleepable && !zpool_can_sleep_mapped(zpool)) { + /* + * If zpool_map_handle is atomic, we cannot reliably utilize its mapped buffer + * to do crypto_acomp_decompress() which might sleep. In such cases, we must + * resort to copying the buffer to a temporary one. + * Meanwhile, zpool_map_handle() might return a non-linearly mapped buffer, + * such as a kmap address of high memory or even ever a vmap address. + * However, sg_init_one is only equipped to handle linearly mapped low memory. + * In such cases, we also must copy the buffer to a temporary and lowmem one. + */ + if ((acomp_ctx->is_sleepable && !zpool_can_sleep_mapped(zpool)) || + !virt_addr_valid(src)) { memcpy(acomp_ctx->buffer, src, entry->length); src = acomp_ctx->buffer; zpool_unmap_handle(zpool, entry->handle); @@ -1094,7 +1104,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct page *page) BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE); mutex_unlock(&acomp_ctx->mutex); - if (!acomp_ctx->is_sleepable || zpool_can_sleep_mapped(zpool)) + if (src != acomp_ctx->buffer) zpool_unmap_handle(zpool, entry->handle); } |