lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 5 Jun 2022 15:38:13 +0100 From: "Matthew Wilcox (Oracle)" <willy@...radead.org> To: Jan Kara <jack@...e.com> Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>, tytso@....edu, Andreas Dilger <adilger.kernel@...ger.ca>, linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org Subject: [PATCH 1/3] quota: Prevent memory allocation recursion while holding dq_lock As described in commit 02117b8ae9c0 ("f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read"), we must not enter filesystem reclaim while holding the dq_lock. Prevent this more generally by using memalloc_nofs_save() while holding the lock. Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org> --- fs/quota/dquot.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index a74aef99bd3d..cdb22d6d7488 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -425,9 +425,11 @@ EXPORT_SYMBOL(mark_info_dirty); int dquot_acquire(struct dquot *dquot) { int ret = 0, ret2 = 0; + unsigned int memalloc; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); mutex_lock(&dquot->dq_lock); + memalloc = memalloc_nofs_save(); if (!test_bit(DQ_READ_B, &dquot->dq_flags)) { ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot); if (ret < 0) @@ -458,6 +460,7 @@ int dquot_acquire(struct dquot *dquot) smp_mb__before_atomic(); set_bit(DQ_ACTIVE_B, &dquot->dq_flags); out_iolock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; } @@ -469,9 +472,11 @@ EXPORT_SYMBOL(dquot_acquire); int dquot_commit(struct dquot *dquot) { int ret = 0; + unsigned int memalloc; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); mutex_lock(&dquot->dq_lock); + memalloc = memalloc_nofs_save(); if (!clear_dquot_dirty(dquot)) goto out_lock; /* Inactive dquot can be only if there was error during read/init @@ -481,6 +486,7 @@ int dquot_commit(struct dquot *dquot) else ret = -EIO; out_lock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; } @@ -492,9 +498,11 @@ EXPORT_SYMBOL(dquot_commit); int dquot_release(struct dquot *dquot) { int ret = 0, ret2 = 0; + unsigned int memalloc; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); mutex_lock(&dquot->dq_lock); + memalloc = memalloc_nofs_save(); /* Check whether we are not racing with some other dqget() */ if (dquot_is_busy(dquot)) goto out_dqlock; @@ -510,6 +518,7 @@ int dquot_release(struct dquot *dquot) } clear_bit(DQ_ACTIVE_B, &dquot->dq_flags); out_dqlock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; } -- 2.35.1
Powered by blists - more mailing lists