From: Alexander Sverdlin alexander.sverdlin@nokia.com
spi_nor_parse_sfdp() modifies the passed structure so that it points to itself (params.erase_map.regions to params.erase_map.uniform_region). This makes it impossible to copy the local struct anywhere else.
Therefore only use memcpy() in backup-restore scenario. The bug may show up like below:
BUG: unable to handle page fault for address: ffffc90000b377f8 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 4 PID: 3500 Comm: flashcp Tainted: G O 5.4.53-... #1 ... RIP: 0010:spi_nor_erase+0x8e/0x5c0 Code: 64 24 18 89 db 4d 8b b5 d0 04 00 00 4c 89 64 24 18 4c 89 64 24 20 eb 12 a8 10 0f 85 59 02 00 00 49 83 c6 10 0f 84 4f 02 00 00 <49> 8b 06 48 89 c2 48 83 e2 c0 48 89 d1 49 03 4e 08 48 39 cb 73 d8 RSP: 0018:ffffc9000217fc48 EFLAGS: 00010206 RAX: 0000000000740000 RBX: 0000000000000000 RCX: 0000000000740000 RDX: ffff8884550c9980 RSI: ffff88844f9c0bc0 RDI: ffff88844ede7bb8 RBP: 0000000000740000 R08: ffffffff815bfbe0 R09: ffff88844f9c0bc0 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc9000217fc60 R13: ffff88844ede7818 R14: ffffc90000b377f8 R15: 0000000000000000 FS: 00007f4699780500(0000) GS:ffff88846ff00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc90000b377f8 CR3: 00000004538ee000 CR4: 0000000000340fe0 Call Trace: part_erase+0x27/0x50 mtdchar_ioctl+0x831/0xba0 ? filemap_map_pages+0x186/0x3d0 ? do_filp_open+0xad/0x110 ? _copy_to_user+0x22/0x30 ? cp_new_stat+0x150/0x180 mtdchar_unlocked_ioctl+0x2a/0x40 do_vfs_ioctl+0xa0/0x630 ? __do_sys_newfstat+0x3c/0x60 ksys_ioctl+0x70/0x80 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x6a/0x200 ? prepare_exit_to_usermode+0x50/0xd0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f46996b6817
Fixes: 1c1d8d98e1c7 ("mtd: spi-nor: Split spi_nor_init_params()") Cc: stable@vger.kernel.org Tested-by: Baurzhan Ismagulov ibr@radix50.net Co-developed-by: Matija Glavinic Pecotic matija.glavinic-pecotic.ext@nokia.com Signed-off-by: Matija Glavinic Pecotic matija.glavinic-pecotic.ext@nokia.com Signed-off-by: Alexander Sverdlin alexander.sverdlin@nokia.com --- drivers/mtd/spi-nor/core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index 2add4a0..cce0670 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -2701,11 +2701,10 @@ static void spi_nor_sfdp_init_params(struct spi_nor *nor)
memcpy(&sfdp_params, nor->params, sizeof(sfdp_params));
- if (spi_nor_parse_sfdp(nor, &sfdp_params)) { + if (spi_nor_parse_sfdp(nor, nor->params)) { + memcpy(nor->params, &sfdp_params, sizeof(*nor->params)); nor->addr_width = 0; nor->flags &= ~SNOR_F_4B_OPCODES; - } else { - memcpy(nor->params, &sfdp_params, sizeof(*nor->params)); } }