Messages in this thread | | | Subject | Re: [PATCH -next 1/2] ext4: fix potential memory leak in ext4_fc_record_regions() | From | yebin <> | Date | Tue, 20 Sep 2022 09:07:57 +0800 |
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On 2022/9/20 2:40, Damien Guibouret wrote: > Hello, > > Le 19/09/2022 à 16:40, Ye Bin a écrit : >> As krealloc may return NULL, in this case 'state->fc_regions' may not be >> freed by krealloc, but 'state->fc_regions' already set NULL. Then will >> lead to 'state->fc_regions' memory leak. >> >> Signed-off-by: Ye Bin <yebin10@huawei.com> >> --- >> fs/ext4/fast_commit.c | 14 ++++++++------ >> 1 file changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c >> index 9217a588afd1..cc8c8db075ba 100644 >> --- a/fs/ext4/fast_commit.c >> +++ b/fs/ext4/fast_commit.c >> @@ -1677,15 +1677,17 @@ int ext4_fc_record_regions(struct super_block >> *sb, int ino, >> if (replay && state->fc_regions_used != state->fc_regions_valid) >> state->fc_regions_used = state->fc_regions_valid; >> if (state->fc_regions_used == state->fc_regions_size) { >> + struct ext4_fc_alloc_region *fc_regions; >> + >> state->fc_regions_size += >> EXT4_FC_REPLAY_REALLOC_INCREMENT; >> - state->fc_regions = krealloc( >> - state->fc_regions, >> - state->fc_regions_size * >> - sizeof(struct ext4_fc_alloc_region), >> - GFP_KERNEL); >> - if (!state->fc_regions) >> + fc_regions = krealloc(state->fc_regions, >> + state->fc_regions_size * >> + sizeof(struct ext4_fc_alloc_region), >> + GFP_KERNEL); >> + if (!fc_regions) > > Would it not be safer to restore state->fc_regions_size to its > previous value in that case to keep consistency between size value and > allocated size (or to update state->fc_regions_size only after > allocation as it is done in second part of this patch) ? > Actually, If 'ext4_fc_record_regions()' return -ENOMEM, then will stop replay journal. 'state->fc_regions_size' will not be used any more, so it's safe. >> return -ENOMEM; >> + state->fc_regions = fc_regions; >> } >> region = &state->fc_regions[state->fc_regions_used++]; >> region->ino = ino; > > Regards, > > Damien > > . >
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