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| author |   Kefeng Wang <wangkefeng.wang@huawei.com> | 2023-04-17 12:53:23 +0800 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2023-05-02 17:21:50 -0700 |
| commit | 245f0922689364b21163af4937a05ea0ba576fae (patch) | |
| tree | c7eafb96828dd9a267c395d38f440a10773d5792 /fs/coredump.c | |
| parent | mm/page_alloc: add some comments to explain the possible hole in __pageblock_pfn_to_page() (diff) | |
| download | wireguard-linux-245f0922689364b21163af4937a05ea0ba576fae.tar.xz wireguard-linux-245f0922689364b21163af4937a05ea0ba576fae.zip | |
mm: hwpoison: coredump: support recovery from dump_user_range()
dump_user_range() is used to copy the user page to a coredump file, but if
a hardware memory error occurred during copy, which called from
__kernel_write_iter() in dump_user_range(), it crashes,
CPU: 112 PID: 7014 Comm: mca-recover Not tainted 6.3.0-rc2 #425
pc : __memcpy+0x110/0x260
lr : _copy_from_iter+0x3bc/0x4c8
...
Call trace:
__memcpy+0x110/0x260
copy_page_from_iter+0xcc/0x130
pipe_write+0x164/0x6d8
__kernel_write_iter+0x9c/0x210
dump_user_range+0xc8/0x1d8
elf_core_dump+0x308/0x368
do_coredump+0x2e8/0xa40
get_signal+0x59c/0x788
do_signal+0x118/0x1f8
do_notify_resume+0xf0/0x280
el0_da+0x130/0x138
el0t_64_sync_handler+0x68/0xc0
el0t_64_sync+0x188/0x190
Generally, the '->write_iter' of file ops will use copy_page_from_iter()
and copy_page_from_iter_atomic(), change memcpy() to copy_mc_to_kernel()
in both of them to handle #MC during source read, which stop coredump
processing and kill the task instead of kernel panic, but the source
address may not always a user address, so introduce a new copy_mc flag in
struct iov_iter{} to indicate that the iter could do a safe memory copy,
also introduce the helpers to set/cleck the flag, for now, it's only used
in coredump's dump_user_range(), but it could expand to any other
scenarios to fix the similar issue.
Link: https://lkml.kernel.org/r/20230417045323.11054-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Tong Tiangen <tongtiangen@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/coredump.c')
| -rw-r--r-- | fs/coredump.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/coredump.c b/fs/coredump.c index 5df1e6e1eb2b..ece7badf701b 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -882,6 +882,7 @@ static int dump_emit_page(struct coredump_params *cprm, struct page *page) pos = file->f_pos; bvec_set_page(&bvec, page, PAGE_SIZE, 0); iov_iter_bvec(&iter, ITER_SOURCE, &bvec, 1, PAGE_SIZE); + iov_iter_set_copy_mc(&iter); n = __kernel_write_iter(cprm->file, &iter, &pos); if (n != PAGE_SIZE) return 0; |