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authorDave Chinner <dchinner@redhat.com>2021-08-09 10:10:00 -0700
committerDarrick J. Wong <djwong@kernel.org>2021-08-09 15:57:43 -0700
commitde2860f4636256836450c6543be744a50118fc66 (patch)
treee66ad295e793855bdcb4774de7afbb815bd197b5 /mm
parent43059d5416c9441aad8f50b96e00f3e8a8a49673 (diff)
mm: Add kvrealloc()
During log recovery of an XFS filesystem with 64kB directory buffers, rebuilding a buffer split across two log records results in a memory allocation warning from krealloc like this: xfs filesystem being mounted at /mnt/scratch supports timestamps until 2038 (0x7fffffff) XFS (dm-0): Unmounting Filesystem XFS (dm-0): Mounting V5 Filesystem XFS (dm-0): Starting recovery (logdev: internal) ------------[ cut here ]------------ WARNING: CPU: 5 PID: 3435170 at mm/page_alloc.c:3539 get_page_from_freelist+0xdee/0xe40 ..... RIP: 0010:get_page_from_freelist+0xdee/0xe40 Call Trace: ? complete+0x3f/0x50 __alloc_pages+0x16f/0x300 alloc_pages+0x87/0x110 kmalloc_order+0x2c/0x90 kmalloc_order_trace+0x1d/0x90 __kmalloc_track_caller+0x215/0x270 ? xlog_recover_add_to_cont_trans+0x63/0x1f0 krealloc+0x54/0xb0 xlog_recover_add_to_cont_trans+0x63/0x1f0 xlog_recovery_process_trans+0xc1/0xd0 xlog_recover_process_ophdr+0x86/0x130 xlog_recover_process_data+0x9f/0x160 xlog_recover_process+0xa2/0x120 xlog_do_recovery_pass+0x40b/0x7d0 ? __irq_work_queue_local+0x4f/0x60 ? irq_work_queue+0x3a/0x50 xlog_do_log_recovery+0x70/0x150 xlog_do_recover+0x38/0x1d0 xlog_recover+0xd8/0x170 xfs_log_mount+0x181/0x300 xfs_mountfs+0x4a1/0x9b0 xfs_fs_fill_super+0x3c0/0x7b0 get_tree_bdev+0x171/0x270 ? suffix_kstrtoint.constprop.0+0xf0/0xf0 xfs_fs_get_tree+0x15/0x20 vfs_get_tree+0x24/0xc0 path_mount+0x2f5/0xaf0 __x64_sys_mount+0x108/0x140 do_syscall_64+0x3a/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Essentially, we are taking a multi-order allocation from kmem_alloc() (which has an open coded no fail, no warn loop) and then reallocating it out to 64kB using krealloc(__GFP_NOFAIL) and that is then triggering the above warning. This is a regression caused by converting this code from an open coded no fail/no warn reallocation loop to using __GFP_NOFAIL. What we actually need here is kvrealloc(), so that if contiguous page allocation fails we fall back to vmalloc() and we don't get nasty warnings happening in XFS. Fixes: 771915c4f688 ("xfs: remove kmem_realloc()") Signed-off-by: Dave Chinner <dchinner@redhat.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/util.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index 9043d03750a7..db3091116b7c 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -635,6 +635,21 @@ void kvfree_sensitive(const void *addr, size_t len)
}
EXPORT_SYMBOL(kvfree_sensitive);
+void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
+{
+ void *newp;
+
+ if (oldsize >= newsize)
+ return (void *)p;
+ newp = kvmalloc(newsize, flags);
+ if (!newp)
+ return NULL;
+ memcpy(newp, p, oldsize);
+ kvfree(p);
+ return newp;
+}
+EXPORT_SYMBOL(kvrealloc);
+
static inline void *__page_rmapping(struct page *page)
{
unsigned long mapping;