Messages in this thread |  | | Date | Mon, 11 Apr 2022 11:09:54 +0800 | Subject | Re: [f2fs-dev] [PATCH] fs: f2fs: remove WARN_ON in f2fs_is_valid_blkaddr | From | Chao Yu <> |
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On 2022/4/9 14:42, Dongliang Mu wrote: > On Sat, Apr 9, 2022 at 11:46 AM Chao Yu <chao@kernel.org> wrote: >> >> On 2022/4/9 9:34, Dongliang Mu wrote: >>> On Sat, Apr 9, 2022 at 8:27 AM Chao Yu <chao@kernel.org> wrote: >>>> >>>> On 2022/4/8 13:22, Dongliang Mu wrote: >>>>> From: Dongliang Mu <mudongliangabcd@gmail.com> >>>>> >>>>> In f2fs_is_valid_blkaddr, if type is DATA_GENERIC_ENHANCE or >>>>> DATA_GENERIC_ENHANCE_READ, it invokes WARN_ON(1) not matter >>>>> blkaddr is in the range or not. >>>> >>>> If we run into the path where we invoke WARN_ON(1) in f2fs_is_valid_blkaddr(), >>>> It means f2fs image may be broken, or there is a bug in f2fs. >>>> >>>> So, do you suffer any related issue in your environment? >>> >>> related issue? Can you explain a little? >>> >>> If you mean if this warning occurs, any other issues or crash >> >> I mean have you seen any warning info printed in the path of >> f2fs_is_valid_blkaddr() before applying this patch, and if so, w/ what >> reproducer? or you just figure out this patch from perspective of code >> review? > > Yes, I have seen both warning information from Syzbot [1] and my local > syzkaller instance. > > In f2fs_is_valid_blkaddr, if the following condition is satisfied, > i.e., blkaddr is not in the right range [2], it will directly invoke > one WARN_ON. > > if (unlikely(blkaddr >= MAX_BLKADDR(sbi) || > blkaddr < MAIN_BLKADDR(sbi))) { > > This is the case on Syzbot. > > Otherwise, it will jump into __is_bitmap_valid. And if the following > condition is satisfied [3], it will trigger another WARN_ON. > > exist = f2fs_test_bit(offset, se->cur_valid_map); > if (!exist && type == DATA_GENERIC_ENHANCE) { > > This appears in my local syzbot instance, but unfortunately it does > not get any reproducer.
Oh, it occurs in syzbot test, I guess it is possible that f2fs prints such warning info after blkaddr of node/data block was fuzzed to invalid one.
I prefer to keep WARN_ON() to catch more info of bugs found by non-fuzzed type test.
Thoughts?
Thanks,
> > [1] https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fbug%3Fextid%3D763ae12a2ede1d99d4dc&data=04%7C01%7Cchao.yu%40oppo.com%7Cff92e63621b24fc75a4908da19f45860%7Cf1905eb1c35341c5951662b4a54b5ee6%7C0%7C0%7C637850834521060840%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=UVSSS9IknYLJHzqqJAN5HmPgJ8GNczvi6%2FuQf2n3vlY%3D&reserved=0 > [2] https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Flatest%2Fsource%2Ffs%2Ff2fs%2Fcheckpoint.c%23L187&data=04%7C01%7Cchao.yu%40oppo.com%7Cff92e63621b24fc75a4908da19f45860%7Cf1905eb1c35341c5951662b4a54b5ee6%7C0%7C0%7C637850834521060840%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=Sf%2Bx8WCAXf5c4%2Bins46saTsTN5uNTrnIceAP3oCWnQw%3D&reserved=0 > [3] https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Flatest%2Fsource%2Ffs%2Ff2fs%2Fcheckpoint.c%23L135&data=04%7C01%7Cchao.yu%40oppo.com%7Cff92e63621b24fc75a4908da19f45860%7Cf1905eb1c35341c5951662b4a54b5ee6%7C0%7C0%7C637850834521060840%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=Ly%2FBL5oFAWZmXwbN6TaYCExroDE8%2Fsli1alaJwR4wvU%3D&reserved=0 > > >> >> Thanks, >> >>> behaviors are generated? I tested on the syzbot. After removing the >>> WARN_ON, there is no abnormal issue or crash behaviors followed with >>> the corresponding reproducer. >>> >>> >>>> >>>> Thanks, >>>> >>>>> >>>>> Fix this by removing WARN_ON. >>>>> >>>>> Note that, syzbot patch testing does not incur any further issues >>>>> >>>>> Reported-by: syzbot+763ae12a2ede1d99d4dc@syzkaller.appspotmail.com >>>>> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> >>>>> --- >>>>> fs/f2fs/checkpoint.c | 2 -- >>>>> 1 file changed, 2 deletions(-) >>>>> >>>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c >>>>> index f5366feea82d..521498b2dd8c 100644 >>>>> --- a/fs/f2fs/checkpoint.c >>>>> +++ b/fs/f2fs/checkpoint.c >>>>> @@ -158,7 +158,6 @@ static bool __is_bitmap_valid(struct f2fs_sb_info *sbi, block_t blkaddr, >>>>> f2fs_err(sbi, "Inconsistent error blkaddr:%u, sit bitmap:%d", >>>>> blkaddr, exist); >>>>> set_sbi_flag(sbi, SBI_NEED_FSCK); >>>>> - WARN_ON(1); >>>>> } >>>>> return exist; >>>>> } >>>>> @@ -196,7 +195,6 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi, >>>>> f2fs_warn(sbi, "access invalid blkaddr:%u", >>>>> blkaddr); >>>>> set_sbi_flag(sbi, SBI_NEED_FSCK); >>>>> - WARN_ON(1); >>>>> return false; >>>>> } else { >>>>> return __is_bitmap_valid(sbi, blkaddr, type); > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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