From: Benjamin Marzinski Date: Tue, 15 Apr 2025 04:17:16 +0000 (-0400) Subject: dm: always update the array size in realloc_argv on success X-Git-Tag: v6.15-rc5~32^2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=5a2a6c428190;p=linux-block.git dm: always update the array size in realloc_argv on success realloc_argv() was only updating the array size if it was called with old_argv already allocated. The first time it was called to create an argv array, it would allocate the array but return the array size as zero. dm_split_args() would think that it couldn't store any arguments in the array and would call realloc_argv() again, causing it to reallocate the initial slots (this time using GPF_KERNEL) and finally return a size. Aside from being wasteful, this could cause deadlocks on targets that need to process messages without starting new IO. Instead, realloc_argv should always update the allocated array size on success. Fixes: a0651926553c ("dm table: don't copy from a NULL pointer in realloc_argv()") Cc: stable@vger.kernel.org Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka --- diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 53759dbbe9d6..9e175c5e0634 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -523,9 +523,10 @@ static char **realloc_argv(unsigned int *size, char **old_argv) gfp = GFP_NOIO; } argv = kmalloc_array(new_size, sizeof(*argv), gfp); - if (argv && old_argv) { - memcpy(argv, old_argv, *size * sizeof(*argv)); + if (argv) { *size = new_size; + if (old_argv) + memcpy(argv, old_argv, *size * sizeof(*argv)); } kfree(old_argv);